Health insurance, healthcare utilization and language use among populations who experience risk for tuberculosis, California 2014-2017.

BACKGROUND: California tuberculosis (TB) prevention goals include testing more than ten million at-risk Californians and treating two million infected with tuberculosis. Adequate health insurance and robust healthcare utilization are crucial to meeting these goals, but information on these factors for populations that experience risk for TB is limited.
METHODS: We used data from the 2014-2017 California Health Interview Survey (n = 82,758), a population-based dual-frame telephone survey to calculate survey proportions and 95% confidence intervals (CI) stratified by country of birth, focusing on persons from countries of birth with the highest number of TB cases in California. Survey proportions for recent doctor's visit, overall health, smoking, and diabetes were age-adjusted.
RESULTS: Among 18-64 year-olds, 27% (CI: 25-30) of persons born in Mexico reported being uninsured in contrast with 3% (CI: 1-5) of persons born in India. Report of recent doctor's visit was highest among persons born in the Philippines, 84% (CI: 80-89) and lowest among Chinese-born persons, 70% (CI: 63-76). Persons born in Mexico were more likely to report community clinics as their usual source of care than persons born in China, Vietnam, or the Philippines. Poverty was highest among Mexican-born persons, 56% (CI: 54-58) and lowest among Indian-born persons, 9% (CI: 5-13). Of adults with a medical visit in a non-English language, 96% (CI: 96-97) were non-U.S.-born, but only 42% (CI: 40-44) of non-U.S.-born persons had a visit in a non-English language. DISCUSSION: Many, though not all, of the populations that experience risk for TB had health insurance and used healthcare. We found key differences in usual source of care and language use by country of birth which should be considered when planning outreach to specific providers, clinic systems, insurers and communities for TB prevention and case-finding.

Introduction

Tuberculosis (TB) is the number one infectious disease killer worldwide causing 1.4 million deaths and ten million new cases of disease in 2019 [1]. In the United States (U.S.), substantial reductions in TB have been achieved though progress has stalled in recent years [2, 3].

California bears a disproportionate share of the TB burden in the U.S. In 2019, there were 2,113 TB cases in California, 24% of all cases nationally despite having 12% of the U.S. population [4, 5]. Country of birth is a major risk factor to TB disease. Of California TB cases, 84% occur among persons born outside the United States and rates of tuberculosis among non-U.S.-born Asians are 50 times higher than among U.S.-born whites [6]. In terms of burden of disease, persons born the United States, Mexico, the Philippines, Vietnam, and India accounted for 80% of persons with TB in California in 2019.

In California, more than 85% of cases result not from recent transmission of TB but from reactivation of latent tuberculosis infection (LTBI) [6, 7]. LTBI is usually acquired in countries of high TB incidence and can remain undiagnosed and untreated for years before progressing to active tuberculosis. To make progress against TB in California, the number of persons that are tested and treated for LTBI needs to be substantially increased. Recent mathematical models support the scale-up of targeted testing and treatment of non-U.S.-born persons for TB infection as important for the reduction of TB in California [8-11]. However, these TB prevention activities rely on access and use of healthcare and our knowledge of these attributes among non-U.S.-born persons is incomplete. In California and elsewhere, public health programs are engaging with community groups especially those focused on healthcare and representing affected communities but more information is needed about the demographics, healthcare utilization and potential barriers to care of populations that experience risk for TB [12-14]. Recent studies have highlighted disparities in healthcare utilization among minority groups but have not focused on non-U.S.-born persons who experience risk for TB [15, 16]. Understanding healthcare utilization of populations that experience risk is important for the planning of TB prevention activities.

One specific barrier to implementing TB prevention is that country of birth, the most important risk factor for TB, is often not captured in the electronic medical record (EMR) [17]. Without country of birth data, technology available in the EMR, such as prompts or reflex testing, cannot be used to promote TB testing among these groups that experience risk. Preferred language at medical visit, which is often populated in EMR data, may be useful as a proxy for country of birth.

Our aim was to describe the health insurance, healthcare utilization and language use of groups that experience risk for TB in California using a large-scale, population-based health survey to inform planning of TB prevention activities. As California transitions from TB control activities focused on finding and treating active TB disease to TB prevention activities requiring latent tuberculosis infection (LTBI) testing and treatment among populations that experience risk for TB, detailed knowledge about the population of the ten million persons in California born outside the U.S. is crucial.

Methods

Data source

Data were drawn from the California Health Interview survey (CHIS) for survey years 2014–2017 [18]. CHIS is an annual population-based telephone survey of California residents that employs both landline and cellphone random digit dialing [19]. Interviews were conducted in English, Spanish, Mandarin, Cantonese, Vietnamese, Korean and Tagalog. Details of the CHIS questionnaire have been published previously [20]. Data were based on respondent self-report and analysis was limited to CHIS adult survey which included persons 18 years and older (n = 82,758). There was insufficient data from the child and teen CHIS sub-surveys to calculate reliable estimates by country of birth.

Definitions

We chose to examine health insurance, healthcare utilization and language use among persons born in Mexico, the United States, the Philippines, Vietnam, China, and India. When stratifying by country of birth, these six countries had the highest number of TB cases in California. Together they accounted for 80% of all cases in California during 2016–2017. Thus, for the purposes of this analysis, we defined populations that experience risk of TB as persons born in these six countries. Poverty was defined as less than 139% of the U.S. federal poverty level. The respondent’s percentage of federal poverty level was calculated using household income earned in the U.S. and household size. Educational attainment was estimated among persons 25 years old and older. Language at medical visit was defined as the language spoken by doctor at last medical visit excluding those who had difficulty communicating with their doctor (<5%) or without a medical visit in last two years. Respondents who did not answer this question but had a medical visit in the last two years and conducted their survey in English were categorized as speaking English at the medical visit. High deductible plans were defined as those plans with an annual deductible of more than $1,000. Delayed or forgone medical care and delayed or forgone medicine were defined as events occurring in the last 12 months; these questions were asked of persons with health insurance in the last 12 months.

Treated unfairly when getting medical care was defined as being treated unfairly sometimes or often when getting medical care over lifetime. Racial or ethnic discrimination was defined as responding yes to the question “was there ever a time when you would have gotten better medical care if you had belonged to a different race or ethnic group?” Usual source of care was condensed from seven categories to three as follows: “doctor’s office”, “health maintenance organization (HMO) or Kaiser” were grouped as “doctor’s office”; “community clinic or hospital” and “government clinic or hospital” were grouped as “community/government clinic/hospital”; categories of “no usual place”, “emergency room”, “urgent care”, “other place”, and “no one place” were grouped into a single category “no usual source.” Data on unfair treatment when getting medical care, perceived racial of ethnic discrimination, and diabetes (non-gestational) were limited to 2015–2017 because these questions were not included in the 2014 survey. Smoking and diabetes were considered because they are risk factors for progression of latent TB infection to TB disease [21, 22].

Statistical analysis

We calculated survey proportions and 95% confidence intervals (CI) stratified by country of birth. We adjusted the following variables by age: doctor’s visit in the last 12 months, overall health, smoking and diabetes. We used the 2017 U.S. Census annual estimate of population for California as the standard population [23]. Survey proportions based on less than three respondents, or 500 weighted respondents were suppressed per California Department of Public Health guidelines for CHIS use. Analysis was done in SAS 9.4. The California Health and Human Services Agency’s Committee for the Protection of Human Subjects (Federal-wide Assurance #00000681) determined that this project was not human subjects research and did not require ethics committee approval or informed consent to be conducted.

Results

Demographic and socioeconomic factors

Demographic and socioeconomic factors of populations that experience risk for TB including sex, age, length of residency in the U.S., education, poverty, and English language proficiency differed by country of birth (Table 1). The proportion of females by country of birth ranged from 60% (CI: 52–68) among Chinese-born persons to 43% (CI: 34–51) among Indian-born persons. The proportion of 18–29 year-olds among U.S.-born was 27% (CI: 27–27) with far lower proportions among persons born outside the U.S., ranging from 8% (CI: 4–11) among those born in Vietnam to 19% (CI: 14–24) among those born in China. Close to three-quarters of persons born in Vietnam or Mexico reported residing in the U.S. for 16 years or more compared with two-thirds of persons born in the Philippines and half of persons born in China or India.

Table 1

TB Burden and demographic characteristics by country of birth, California 2014–2017.

		Philippines	Vietnam	India	China	Mexico	United States
Incidence of TB disease per 100,000 person-years		45	41	25	23	10	1
Proportion of overall TB cases		18	10	5	7	21	19
		% (95% CI)	% (95% CI)	% (95% CI)	% (95% CI)	% (95% CI)	% (95% CI)
Sex
	Female	58 (51–64)	54 (45–62)	43 (34–51)	60 (52–68)	51 (49–52)	51 (50–51)
	Male	42 (36–49)	46 (38–55)	57 (49–66)	40 (32–48)	49 (48–51)	49 (49–50)
Age
	18–29	17 (11–22)	8 (4–11)	19 (12–26)	19 (14–24)	11 (9–12)	27 (27–27)
	30–39	12 (8–16)	14 (9–20)	29 (21–37)	19 (13–24)	23 (21–25)	17 (16–17)
	40–49	22 (16–28)	28 (20–36)	25 (18–32)	24 (18–29)	29 (27–31)	13 (13–14)
	50–59	18 (14–23)	19 (13–24)	12 (6–18)	13 (7–19)	20 (18–22)	16 (15–16)
	60–69	17 (13–22)	18 (11–25)	9 (5–12)	13 (8–17)	12 (10–13)	14 (14–15)
	70–79	10 (7–14)	11 (6–15)	5 (2–9)*	8 (4–13)	4 (3–5)	8 (8–9)
	80+	4 (2–6)	3 (1–5)*	1 (0–3)*	5 (2–7)	1 (1–2)	5 (5–5)
Years in the U.S.
	0–5	11 (6–15)	7 (3–11)	21 (14–29)	19 (14–25)	4 (3–5)
	6–10	12 (8–16)	12 (6–19)	13 (7–19)	16 (10–21)	8 (7–10)
	11–15	12 (8–17)	7 (4–11)	16 (10–23)	12 (8–16)	14 (12–15)
	16+	65 (59–70)	73 (64–81)	49 (41–57)	53 (46–60)	74 (72–76)
Educational Attainment (of 25 years old and older)
	High school/HS equivalent or less	13 (8–19)	55 (48–63)	4 (1–7)*	30 (24–35)	83 (81–85)	27 (26–28)
	Some College/Vocational School/AA or AS	23 (17–29)	10 (7–14)	5 (1–9)*	7 (4–10)	9 (8–10)	28 (27–29)
	BA/BS degree or higher	64 (57–71)	34 (25–43)	91 (87–95)	64 (57–70)	8 (7–9)	45 (44–46)
Poverty Level
	0–138% FPL	26 (20–32)	47 (39–55)	9 (5–13)	29 (23–35)	56 (54–58)	19 (18–20)
	139%-249% FPL	18 (14–23)	16 (11–21)	8 (4–13)	14 (9–18)	26 (24–28)	16 (15–17)
	250%-399% FPL	18 (13–22)	10 (6–14)	15 (8–21)	15 (10–20)	11 (10–13)	18 (17–19)
	400%+ FPL	38 (32–45)	27 (19–35)	68 (60–75)	42 (35–49)	7 (5–8)	47 (46–48)
Language spoken at home
	English only	22 (17–28)	7 (1–12)*	9 (5–13)	7 (4–10)	2 (1–3)
	Language of country of birth and English	59 (54–65)	30 (22–37)	70 (62–78)	34 (28–41)	47 (44–49)
	Other including multiple non-English languages	9 (6–13)	11 (6–16)	7 (3–11)*	12 (7–18)	2 (1–2)
	Language of country of birth only	9 (6–12)	53 (45–61)	14 (9–19)	46 (39–53)	50 (47–52)
English language proficiency
	Speaks English only	22 (17–28)	7 (1–12)*	9 (5–13)	7 (4–10)	2 (1–3)	77 (76–78)
	Very well/Well	71 (64–77)	40 (32–48)	89 (85–94)	54 (47–60)	31 (29–33)	23 (22–24)
	Not well/Not at all	7 (3–12)*	53 (45–61)	1 (0–3)*	39 (33–45)	67 (65–69)	1 (0–1)

Source: Data on TB incidence and burden are from the Tuberculosis Control Branch, California Department of Public Health 2017; All other data from California Health Interview Survey, 2014–2017.

Notes

* Statistically unstable—Coefficient of Variation > 0.3.

There were substantial differences in educational attainment by country of birth. Of persons born in Vietnam, 55% (CI: 48–63) had a high school education or less. Among persons born in Mexico, that estimate was 83% (CI: 81–85). In comparison, the proportion with a high school education or less was 13% (CI: 8–19) among persons born in the Philippines. Poverty followed similar patterns to educational attainment, with some notable differences. Among persons born in Mexico or Vietnam, 56% (CI: 54–58) and 47% (CI: 37–55) respectively lived in poverty. In contrast, 19% (CI: 18–20) and 9% (CI: 5–13) of persons born in the U.S. or India lived in poverty. Also, most non-U.S.-born persons had resided in the U.S. for 16 or more years, across all countries of birth.

Health insurance

Patterns of healthcare insurance were also notably different (Table 2). The proportion of 18–64 year-olds who were uninsured ranged from 27% (CI: 25–30) among persons born in Mexico to 3% (CI: 1–7) among persons born in India. Among persons 65 years old and older, the proportion who reported both Medicare and Medi-Cal coverage ranged from 14% (CI: 12–16) among U.S.-born to 72% (CI: 59–84) among persons born in Vietnam. More than half of Indian-born persons, 51% (CI: 39–62), reported high deductible health insurance plans in contrast to a third of U.S.-born persons who reported the same, 33% (CI: 32–34).

Table 2

Healthcare access and utilization by country of birth, California 2014–2017.

		Philippines	Vietnam	China	India	Mexico	United States
Health insurance (18–64)
	Employment-Based /Privately Purchased	63 (56–71)	54 (44–64)	70 (64–76)	88 (82–93)	32 (30–34)	65 (64–66)
	Medi-Cal/ Medicare/ Other Public	24 (17–32)	34 (24–44)	19 (13–24)	10 (4–15)	41 (38–44)	26 (25–27)
	Uninsured	12 (8–17)	12 (6–17)	11 (7–15)	3 (1–5)*	27 (25–30)	9 (8–9)
Health insurance (65+)
	Medicare + Medi-Cal	37 (27–47)	72 (59–84)	37 (22–53)	17 (0–38)*	50 (44–56)	14 (12–16)
	Medicare + Other	48 (37–59)	20 (10–30)	53 (37–69)	60 (38–81)	32 (26–38)	75 (73–77)
	Medicare Only, Other Only and Uninsured	15 (6–23)*	8 (0–17)*	10 (3–17)*	23 (5–41)*	18 (13–23)	11 (10–12)
High deductible (of employer/private insured)		38 (30–47)	43 (29–58)	46 (35–58)	51 (39–62)	39 (35–42)	33 (32–34)
Usual source of care
	Doctor’s Office	55 (48–63)	73 (66–81)	55 (49–62)	61 (53–69)	31 (28–34)	65 (64–67)
	Community/government clinic or hospital	29 (23–36)	7 (4–10)	27 (20–33)	28 (20–36)	41 (38–45)	19 (18–20)
	No Usual Source	15 (11–19)	19 (13–26)	18 (13–23)	11 (6–15)	28 (26–30)	15 (14–16)
Visited doctor in last 12 months §		84 (80–89)	76 (67–85)	70 (63–76)	82 (76–88)	73 (71–75)	83 (83–84)
Hard time understanding doctor at last visit		1 (0–3)*	6 (2–10)*	6 (3–9)	‡	7 (5–8)	3 (2–3)
Delayed or forgone prescription drugs		7 (4–11)	4 (1–7)*	4 (2–7)	6 (0–13)*	9 (8–11)	11 (11–12)
Delayed or forgone medical care		7 (4–10)	7 (2–12)*	7 (4–10)	8 (4–12)	10 (9–11)	14 (14–15)
Treated unfairly when getting medical care†		9 (5–13)	11 (5–16)	7 (3–11)	11 (3–19)*	14 (11–17)	10 (10–11)
Racial or ethnic discrimination†		2 (0–4)*	6 (2–10)*	8 (2–13)*	7 (0–14)*	6 (5–8)	4 (4–5)
Excellent/very good overall health §		52 (46–58)	29 (21–38)	46 (39–53)	62 (52–71)	26 (24–28)	54 (52–55)
Smoking §
	Currently Smokes	8 (5–12)	11 (6–17)	7 (3–10)	4 (1–7)	10 (8–11)	13 (13–14)
	Quit Smoking	19 (14–23)	8 (4–12)	8 (5–12)	10 (6–15)	18 (16–20)	24 (23–25)
	Never Smoked Regularly	73 (67–79)	81 (74–87)	85 (80–90)	86 (80–91)	73 (70–75)	63 (62–64)
Ever told had diabetes (excludes gestational)†§		15 (9–20)	7 (4–10)	7 (3–11)*	9 (4–14)	17 (15–19)	8 (8–9)

Source: California Health Interview Survey, 2014–2017.

Notes

* Statistically unstable—coefficient of variation > 0.3

§ Age adjusted

‡ Estimate suppressed per California Health Interview Survey guidelines

† Data not available for 2014. Estimate calculated using 2015–2017 data.

Healthcare utilization and barriers to care

The proportion of persons reporting visiting a doctor in the last 12 months differed by country of birth, even after age adjustment (Table 2). Report of age-adjusted recent doctor’s visit was highest among persons born in the Philippines, 84% (CI: 80–89) and lowest among Chinese-born persons, 70% (CI: 63–76). Age-adjusted recent doctor’s visit among persons born in the U.S. was 83% (CI: 83–84).

There was also a substantial difference in usual source of care by country of birth (Table 2). The proportion reporting a doctor’s office as usual source of care was highest among Vietnamese-born persons at 73% (CI: 66–81) and lowest among Mexican-born persons, 31% (CI: 24–34). The proportion reporting no usual source of care was highest among Mexican-born persons at 28% (CI: 26–30) and lowest among Indian-born persons at 11% (CI: 6–15).

The proportion of persons experiencing barriers to care was low. Whereas 11% (CI: 11–12) of U.S.-born persons had delayed or forgone medicine, 4% (CI: 2–7) of Chinese-born persons had done the same. Similarly, 14% (14%-15%) of U.S.-born persons had delayed or forgone medical care, whereas 7% (4–10) of Chinese-born persons had done the same.

Few people reported racial discrimination and unfair treatment, and, in the case of discrimination, variable by country of birth though these estimates were statistically unstable. Of U.S.-born persons, 10% (CI: 9–11) reported being treated unfairly sometimes or often when getting medical care. Of persons born Mexico, 14% (CI: 11–16) reported the same. In contrast, of persons born in China 7% (CI: 3–11) reported this. Less than 10% reported having a hard time understanding the doctor at last visit with the highest proportion among Mexican-born persons at 7% (CI: 5–8) and Chinese-born persons 6% (CI: 2–9). For comparison, the estimate was 3% (CI: 2–3) for U.S.-born persons.

Overall health and risk factors for TB reactivation

Age-adjusted overall health differed widely by country of birth (Table 2). Among U.S.-born, 54% (CI: 52–55) reported very good or excellent health. Lower proportions of good or excellent health were reported by persons born in Mexico or in Vietnam: 26% (CI: 24–28) and 29% (CI: 21–38). The highest proportion with very good or excellent health was among persons born in India at 62% (CI: 52–71).

Current smoking was highest among persons born in Vietnam 11% (CI: 6–17) though the confidence interval was wide. Persons born in Mexico, or the Philippines reported high proportions of former smoking, 18% (CI: 16–20) and 19% (CI: 14–23) respectively. Of persons born in the U.S., 24% (CI: 23–25) reported former smoking. Former smoking was lower among persons born in Vietnam, China, or India, 8% (CI: 4–12), 8% (CI: 5–12) and 10% (CI: 6–15) respectively.

Of persons born in Mexico or the Philippines, 17% (CI: 14–19) and 17% (CI: 12–23) reported diabetes respectively (age-adjusted). Diabetes proportions were lower among persons born in Vietnam, China, and India, similar to the level observed among the U.S.-born, 8% (CI: 8–9).

Language at medical visit and at home

Non-English language use at medical visit was indicative of birth outside the U.S.; of adults with a medical visit in a non-English language, 96% (CI: 96–97) were non-U.S.-born (Table 3). However, of non-U.S.-born, 42% (CI: 40–44) had medical visits in a non-English language. As a proxy for nativity, language at medical visit had a low sensitivity (42%) and a high specificity (99%) (Table 3).

Table 3

Language at medical visit by nativity, California 2014–2017.

	Non-U.S.-born	U.S.-born
Non-English	3,509,456	128,524	3,637,980
English	4,839,626	17,281,183	22,120,809
	8,349,082	17,409,707	25,758,789
	Sensitivity	42%
	Specificity	99%
	Positive predictive value	96%
	Negative predictive value	78%

Source: California Health Interview Survey, 2014–2017.

Note: Weighted totals are presented.

Further stratifying by language used, we see that non-English language use was correlated closely with non-U.S. birth across languages (Table 4). Of persons with visits in Tagalog, 96% (CI: 88–100) were born in the Philippines. Of persons with visits in Vietnamese, 96% (CI: 92–100) were born in Vietnam. Proportion non-U.S.-born for visits in Mandarin, Cantonese or an Asian Indian language were similar. Of persons with visits in Spanish, 78% (CI: 75–81) were born in Mexico and 19% (CI: 12–21) elsewhere outside the U.S.

Table 4

Proportion country of birth by language spoken in medical visit, California 2014–2017.

Language	United States % (95% CI)	Philippines % (95% CI)	Vietnam % (95% CI)	China % (95% CI)	India % (95% CI)	Korea % (95% CI)	Mexico % (95% CI)	Other Country
English	78 (78–79)	3 (2–3)	1 (1–1)	1 (1–1)	1 (1–2)	0 (0–1)	6 (6–7)	9 (8–10)
Tagalog		96 (88–100)
Vietnamese	2 (0–4)*		96 (92–100)
Mandarin	4 (0–8)*		2 (0–3)**	70 (59–80)				22 (13–32)
Cantonese			8 (0–26)**	85 (66–100)				6 (0–14)*
Asian Indian Languages					80 (49–100)			14 (0–42)*
Korean						99 (96–100)
Spanish	4 (3–5)						78 (75–81)	19 (16–21)

Source: California Health Interview Survey, 2014–2017

Notes

* Statistically unstable—Coefficient of Variation > 0.3.

The language used at medical visit varied widely by country of birth (S1 Table). Among persons born in Mexico or Vietnam, 38% (CI: 36–41) and 41% (CI: 31–50) had visits in English; similar results were found for persons born in China. In contrast, among persons born in India or the Philippines, 96% (CI: 94–99) and 91% (CI: 87–95) had a visit in English. Of U.S.-born, 0.7% (CI: 0.5–0.9) had visits in a non-English language.

Of adults who did not speak English at home, 89% (CI: 88–90) were non-U.S.-born. Among non-U.S.-born, 43% (CI: 41–44) did not speak English at home. The proportion of persons residing in households in which no English was spoken ranged widely by country of birth (Table 1). Of persons born in the Philippines, 9% (CI: 6–12) spoke only Tagalog at home and, of persons born in India, 14% (CI: 9–19) spoke only an Asian Indian language at home. In contrast, 53% (CI: 46–61) of persons born in Vietnam spoke only Vietnamese at home and 50% (CI: 47–52) of persons born in Mexico spoke only Spanish at home. English proficiency estimates followed similar patterns.

Discussion

In our analysis of a representative self-reported health survey focusing on non-U.S.-born populations that experience risk for tuberculosis, we have identified five findings that could help inform future TB prevention activities in California and across the U.S. These findings present opportunities and signal potential pitfalls for planning outreach to specific providers, clinic systems, insurers, and communities.

First, most persons who experience risk for TB had health insurance and were engaged with medical care. Analyses of health insurance coverage among non-U.S.-born persons using a variety of national datasets have reported similar results [24-26]. Barriers to healthcare access and utilization, such as cost and racial/ethnic discrimination, affected less than one in ten persons. Racial or ethnic discrimination has been shown to reduce access care and filling of prescriptions which would hamper TB prevention activities [27, 28]. With the notable exceptions of persons experiencing homelessness and one quarter of persons born in Mexico who are uninsured, the hurdle of getting populations that experience risk into care has largely been met. Future efforts should focus on encouraging patients who experience risk to ask for TB testing and treatment and aiding providers in their efforts to test and treat persons already in care. Public awareness campaigns could consider intervening with patients at or around the point of care.

Second, populations that experience risk had notably different usual sources of care. In agreement with previous studies, persons born in Mexico were more likely to use community or government facilities or to have no usual source of care than other populations that experience risk [26]. Although community and government providers are natural partners for public health programs, persons born in countries with the highest TB rates like Vietnam and the Philippines were less likely to use these providers. While more than a third of Vietnamese-born 18–64 year-olds and one-fifth of those over 65 years old had public insurance, less than one in ten used government or community facilities. Consistent with other reports, this finding suggests that efforts to reach populations that experience risk should not focus solely on public healthcare systems and publicly funded clinics but must engage both public and private healthcare systems [25]. In addition, type of health insurance alone cannot predict the usual source of care in these populations that experience risk. As is shown with insurance and access patterns of the Vietnamese-born above, persons with government insurance like Medi-Cal do not necessarily use government or community clinics. This is important to keep in mind when considering type of health insurance as a proxy for usual source of care.

Third, risk factors for the progression of latent TB infection to TB disease varied widely among the populations surveyed. Diabetes and smoking are associated with increased risk of progression of latent TB infection to active TB disease [21, 22]. Overall health may be associated with TB disease [29]. Self-reported diabetes among Philippines-born and Mexican-born persons was more than double the rates for persons born in other countries including the U.S., similar to prior work [30, 31]. Likewise, former smoking was twice as high among Philippines-born and Mexican-born persons than among persons born in China, India or Vietnam as has been previously documented [32, 33]. The prevalence of these risk factors among populations who already experience risk for TB provides opportunities for engagement with providers who may not currently think about TB even when seeing persons who experience risk for the disease. One engagement strategy could be using a common comorbidity such as diabetes as an entry point for provider education about TB. It also highlights an opportunity to collaborate with organizations which focus on these comorbidities. The dual intervention of smoking cessation and latent TB infection targeted testing and treatment could have a powerful effect by averting costly and deadly disease in key groups.

Fourth, there were prominent differences in the demography of populations that experience risk that could inform the way in which these populations are engaged. Persons born in Mexico or Vietnam were more likely to be long-term residents of the U.S., have lower education attainment, higher poverty levels and lower self-reported overall health in comparison to persons born in the Philippines, China, or India. Roughly, one-fifth of U.S.-born persons lived in poverty whereas one quarter to one half of persons born in Mexico, Vietnam, China, or the Philippines were impoverished. Less than one in 10 persons born in India lived in poverty. In addition, persons born in Mexico, Vietnam or China were more likely not to speak English at their medical visit or at home than persons born in India or the Philippines. This information, especially language use and educational attainment, has immediate, practical use in tailoring public-facing campaigns, specifically the languages and reading levels in which educational materials are offered.

Fifth, we investigated whether language at medical visit could be used to identify persons born outside the U.S. We found that persons who used a language other than English at their medical visit were highly likely to be born outside the U.S. Thus, preferred language may be suitable as a starting point for identifying high-risk subgroups. However, non-English language at medical visit identified only half of all non-U.S.-born persons. EMRs should be modified to accommodate country of birth data, which is commonly missing in these records, and workflows should be adjusted to collect these data. Without country of birth data, a large portion of the population who experience risk could be missed. Even with system modifications, previous reports have noted that collection of these data can be difficult to navigate with patients [34]. Still, use of preferred language to identify patients who experience risk could reduce a major barrier to implementing TB prevention activities in large health systems where country of birth, the most important risk factor for latent TB infection, is often not captured.

Language used at medical visit and at home were roughly concordant which provides an opportunity to use language at home when language at medical visit is not available. Non-English speaking persons could be at increased risk for TB compared with other persons from the same country because previous studies have shown non-U.S.-born persons with low educational attainment are at increased risk of TB and, from our analysis, we see non-U.S.-born persons with low educational attainment are more likely not to speak English [35, 36].

This analysis has several limitations. Recent shifts in employment and health insurance coverage due to the COVID-19 pandemic may reduce the applicability of this work. Updates to these analyses will be necessary. These results are most useful if, within country of birth strata, persons with LTBI have similar health care access and utilization patterns as those without LTBI. A recent national analysis suggests that this is the case [25]. While recent analyses have detailed heterogeneity in health insurance coverage by immigration legal status, similar analyses were not possible here because these data were not collected [26]. Also, data useful to describing TB risk such as travel to country of origin and household crowding were not available. The survey was conducted by phone and may under-represent persons who are less likely to answer the phone, such as persons experiencing homelessness, young adults, and non-English speakers. Furthermore, it relies on participant self-report which may underestimate key determinants of TB risk, such as poverty and country of origin, because of social desirability bias. Because this analysis focuses on non-U.S.-born persons, and persons experiencing homelessness maybe under-represented, it would be helpful to know the proportion of non-U.S.-born persons who experience homelessness in California. Unfortunately, there is no statewide estimate for non-U.S.-born homelessness, but a recent study found the proportion of lifetime homelessness among non-U.S.-born persons was 1% [37]. However, from California TB data, homelessness was less common among non-U.S.-born persons with TB at 3.6%. Among U.S.-born cases that proportion was 15.2%. Language used by patient at medical visit was not assessed in the survey; language used by doctor at medical visit was used instead. Data on providers serving these populations at-risk for TB was not available limiting the ability to identify these providers for potential awareness campaigns.

Conclusion

Our analysis points out several important differences by country of birth in demography, healthcare utilization, and language use among populations that experience risk for TB. These differences present opportunities and signal potential pitfalls for planning outreach to specific communities that experience risk for TB and the providers, clinic systems, health insurers and health insurance purchasers who serve them. These data could be used to inform public awareness campaigns, provider education, academic detailing, and community outreach efforts. We envision these efforts will be multi-faceted, multi-sectorial, and adapted to specific communities and providers and that they include input from populations that experience risk for TB. While the information here most directly supports this tailored approach in California, we believe that similarly crafted approaches would help TB prevention efforts in other states across the U.S. as well.

Proportion language spoken in medical visit by country of birth, California 2014–2017.

(DOCX)

Click here for additional data file.

24 May 2021

PONE-D-21-08860

Navigating toward TB elimination: the California perspective.

PLOS ONE

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Reviewer #1: It would be nice to have input from your populations of interest (foreign born people) – either to put in this paper, or as future steps as you engage with providers and patients at risk. Also, what is currently being done in terms of outreach to specific communities? What have other states done? Nice to have more CA specific background stats on TB and more specifically immigrant populations – what makes CA different/better/worse than other states?

Not sure why looking at attitudes/feelings around discrimination – while interesting, they don’t really add to the efforts/next steps around TB prevention (or this wasn’t made clear in the paper)

Line 230 – not clear what % of homeless are foreign born. They couldn’t be surveyed, so how do we know they are not a large %?

Need to clearly elucidate next steps with regard to improving EMR documentation of country of birth

Is there anything that can be included in the next statewide survey to help this TB campaign?

Good point about leveraging comorbidity work (smoking/diabetes).

It seems like different countries at birth (e.g. Mexico) have different needs – maybe focus on some of those. County of birth being Mexico has the largest proportion of TB cases (in Table 1, 21), and in lines 230-231 you state ¼ are uninsured – seems like a good part to focus prevention efforts on. This pop also has a high percentage of diabetes.

Focus on provider education in terms of increased testing for TB in this population/routine testing (not patient – in line 232). And who are these providers caring for foreign born populations? (do they differ than other providers?)

What about the following factors in describing your pop of interest: legal status (esp for people interested in obtaining legal status – might be less likely to utilize any services out of fear of jeopardizing their future greencards), travel back to country of origin (perhaps this is where they get TB, thru travel, and not just coming into the US with it), age at immigration to US, household size/make up of extended family (and if they have travel back to at-risk countries, or issues of household crowding making it easier to spread TB).

Would be nice know breakdown of active TB cases (foreign born vs. US born), does this follow the same patterns as described in this paper?

Table 1 – more “TB Burden” to be at top of table, not at bottom

Table 4 – include percentages

Reviewer #2: Overall, I found this an interesting analysis of the demographic, health, and healthcare seeking characteristics of the non-US born population in California. While this population is certainly important to identify, describe, and understand for TB control, the paper lacks a clearly presented conceptual framework that describes how these demographic and clinical characteristics: 1) impact TB care and outcomes; and 2) are unique to TB. The non-USB population is at risk for a variety of conditions (Hepatitis, COViD, e.g.) making it important to clearly describe the context for focus on non-USB more explicitly in the introduction. A conceptual framework for why each of these data fields from CHIS were chose would also be helpful, especially for readers not as familiar with the domestic TB literature.

Please specify in Methods why you focus on 5 countries named (assuming based on country of origin for most TB cases in CA?).

Suggest a citation for this statement as it forms a key underlying premise for the purpose of the paper (ln 67)” One specific barrier to implementing TB prevention in large health systems is that country of 68 birth, the most important risk factor for TB, is often not captured in the electronic medical 69 record (EMR).”

This statement does not seem to make sense (ln 277-278) “Our results show that non-English language at medical visit was an excellent proxy for non-U.S. 278 birth, but identified only half of all non-U.S.-born persons.” How is a proxy excellent if it only identifies half of the eligible population? Please refer to the 2-way table you present in results as to how you would like the reader to interpret this statement. Are you say that the positive predictive value or specificity is high but sensitivity is low? If so, please state as such.

Please describe important limitations of using CHIS data, ie, sampling bias based on phone and self-response and how this may actually underestimate the prevalence of some of those key sociodemographic determinants that affect TB care.

Table 3 is challenging to read and interpret. Suggest revising.

You may want to consider using the first paragraph of the Discussion as the last paragraph of the Introduction, as it is the first place that seems to clearly articulate the purpose for the analysis presented.

Reviewer #3: This is an interesting paper. It has the potential benefits in the field of TB in the USA. But to let it be strong enough, some clarifications are needed. Below are some suggestions which could help improve the paper if the authors found them relevant.

- I would suggest to further explain the methodology. I’m a little bit concerned with the methodology section as presented. The methods section should be clearly and unambiguously stated. I find that there are many references that are indicated and that unfortunately hide a lot of details. For example, the methodology does not show the countries or let's say the different nationalities (India, Mexico, USA, Philippine, Vietnam, etc.) mentioned in the results section. Is there any link or relationship between individuals regarding their nationalities and the risk to get TB? Also, what is the threshold and the criteria of poverty according to the place of birth? According to the fact that poverty in the US could be completely different of the one in Philippine or somewhere else…

- HMO. I don’t know what this acronym means! Please put the definition in bracket (p.99)

- In most of the items presented in the results section, it is not easy to perceive the link between the different factors (diabetes, smoking, good or bad health, etc.) mentioned and their relationship with TB. The authors should discuss this further.

- The discussion section, as presented, in my opinion is more a part where the authors interpret their results and not discussing them. The discussion, as its name indicates, should be the place where the results, while being interpreted, are also confronted with the studies of other authors and where the points of view are clearly confirmed, refuted or nuanced. And this should be felt in the richness of the references mentioned in the said section. But, as we can see here, the authors have mentioned only 2 references in this whole long discussion... And besides, the article is not rich enough in terms of bibliographic references. So, I suggest to enrich it further, if only with a little more reading...

- Where is the conclusion section? And what are the main conclusions of the data obtained from the California Health Interview survey (CHIS)?

- What could be the concrete added value of this article? What contribution and especially how can the results obtained contribute to the elimination of TB in the whole USA in general or at least in California more specifically? This is not clear in the paper.

**********

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31 Aug 2021

Response to editor’s and reviewers’ comments:

Editor

1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at

DONE.

2. In your Methods section, please provide additional information about the analysis performed, for example how many participants were included.

DONE. Methods now include the line: “Data were based on respondent self-report and analysis was limited to persons 18 years and older (n=82,758).”

3. Please consider modifying your title to ensure that it is specific and descriptive.

DONE. The manuscript is now titled “Demographics and healthcare utilization of populations at risk for tuberculosis, California 2014-2017.”

4. We note that you have indicated that data from this study are available upon request. PLOS only allows data to be available upon request if there are legal or ethical restrictions on sharing data publicly. For information on unacceptable data access restrictions, please see http://journals.plos.org/plosone/s/data-availability#loc-unacceptable-data-access-restrictions.

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4a) If there are ethical or legal restrictions on sharing a de-identified data set, please explain them in detail (e.g., data contain potentially identifying or sensitive patient information) and who has imposed them (e.g., an ethics committee). Please also provide contact information for a data access committee, ethics committee, or other institutional body to which data requests may be sent.

DONE. Addressed in cover letter.

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DONE. Ethics statement now included in methods section and deleted from other sections.

6. Please include your tables as part of your main manuscript and remove the individual files. Please note that supplementary tables (should remain/ be uploaded) as separate "supporting information" files

DONE. Tables are now included as part of main manuscript file.

Reviewers' comments

Reviewer #1: It would be nice to have input from your populations of interest (foreign born people) – either to put in this paper, or as future steps as you engage with providers and patients at risk.

Revised to address comment: “We envision these efforts will be multi-faceted, multi-sectorial, and adapted to specific communities and providers and that they include input from populations at risk for TB”

Also, what is currently being done in terms of outreach to specific communities? What have other states done?

Added the following text to the introduction: “In California and elsewhere, public health programs are engaging with community groups especially those focused on healthcare and representing affected communities…”

Nice to have more CA specific background stats on TB and more specifically immigrant populations – what makes CA different/better/worse than other states?

Added CA background statistics to the introduction: “California bears a disproportionate share of the TB burden in the U.S. In 2019, there were 2,113 TB cases in California, 24% of all cases nationally despite having 12% of the U.S. population [4, 5]. Of Californian TB cases, 84% occur among persons born outside the United States and rates of tuberculosis among non-US-born Asians are 50 times that among US-born whites [6].”

Not sure why looking at attitudes/feelings around discrimination – while interesting, they don’t really add to the efforts/next steps around TB prevention (or this wasn’t made clear in the paper)

Revised manuscript to underscore the connection between racial discrimination and TB prevention activities. “Barriers to healthcare access and utilization, such as cost and racial/ethnic discrimination, affected less than one in ten persons. Racial or ethnic discrimination has been shown to reduce access care and filling of prescriptions which would hamper TB prevention activities [26, 27].”

Line 230 – not clear what % of homeless are foreign born. They couldn’t be surveyed, so how do we know they are not a large %?

Important point. We added a section in the limitations to address this issue: “Because this analysis focuses on non-U.S.-born persons and persons experiencing homelessness maybe under-represented, it would be helpful to know the proportion of non-U.S.-born persons who experience homelessness in California. Unfortunately, there is no statewide estimate for non-U.S.-born homelessness, but a recent study found the proportion of lifetime homelessness among non-U.S.-born persons was 1% [28].”

Need to clearly elucidate next steps with regard to improving EMR documentation of country of birth. Is there anything that can be included in the next statewide survey to help this TB campaign?

Agreed. Added this language to the discussion of EMRs: “EMRs should be modified to accommodate country of birth data and workflows should be modified to collect these data, without which a large portion of the at-risk population could be missed.”

We continue to work with partners to include TB questions on the statewide survey though to date questions on TB have not been included.

Good point about leveraging comorbidity work (smoking/diabetes).

Agreed. Helpful to know this made sense to the reviewer.

It seems like different countries at birth (e.g. Mexico) have different needs – maybe focus on some of those. County of birth being Mexico has the largest proportion of TB cases (in Table 1, 21), and in lines 230-231 you state ¼ are uninsured – seems like a good part to focus prevention efforts on. This pop also has a high percentage of diabetes.

We have identified several populations that require increase testing and treatment. From the conclusion: “We envision these efforts will be multi-faceted, multi-sectorial, and adapted to specific communities and providers and that they include input from populations at risk for TB.”

Focus on provider education in terms of increased testing for TB in this population/routine testing (not patient – in line 232). And who are these providers caring for foreign born populations? (do they differ than other providers?)

We believe that both patient and provider awareness is important to successful intervention to increase testing and treatment. Provider engagement is discussed in the context of co-morbidities: “The prevalence of these risk factors among populations already at risk for TB provides opportunities for engagement with providers who may not currently think about TB even when seeing persons at risk for the disease. One engagement strategy could be using a common comorbidity such as diabetes as an entry point for provider education about TB.”

With regard to details on the providers who serve the population at risk, we are limited by this survey questionnaire which does not include much data on providers beyond language used at visit and the patient’s usual source of care.

What about the following factors in describing your pop of interest: legal status (esp for people interested in obtaining legal status – might be less likely to utilize any services out of fear of jeopardizing their future greencards), travel back to country of origin (perhaps this is where they get TB, thru travel, and not just coming into the US with it), age at immigration to US, household size/make up of extended family (and if they have travel back to at-risk countries, or issues of household crowding making it easier to spread TB).

We are limited by the survey questionnaire which does not include data on travel to country of origin.

Would be nice know breakdown of active TB cases (foreign born vs. US born), does this follow the same patterns as described in this paper?

Added the following to the introduction: “California bears a disproportionate share of the TB burden in the U.S. In 2019, there were 2,113 TB cases in California, 24% of all cases nationally despite having 12% of the U.S. population [4, 5]. Of Californian TB cases, 84% occur among persons born outside the United States and rates of tuberculosis among non-US-born Asians are 50 times that among US-born whites [6].”

Table 1 – more “TB Burden” to be at top of table, not at bottom

Revised per comment.

Table 4 – include percentages

Other reviewers also commented on this table. I have revised the table to be more understandable. Percentages are included.

Reviewer #2: Overall, I found this an interesting analysis of the demographic, health, and healthcare seeking characteristics of the non-US born population in California. While this population is certainly important to identify, describe, and understand for TB control, the paper lacks a clearly presented conceptual framework that describes how these demographic and clinical characteristics: 1) impact TB care and outcomes; and 2) are unique to TB.

�  Re-wrote introduction to address lack of conceptual framework and to describe how healthcare utilization is important in planning TB prevention activities. Essentially, TB prevention activities rely on access and use of healthcare. One of the main interventions is to have persons at-risk for TB be tested by their doctor and treated if needed.

The non-USB population is at risk for a variety of conditions (Hepatitis, COViD, e.g.) making it important to clearly describe the context for focus on non-USB more explicitly in the introduction.

�  Add context for the focus on non-USB in introduction: “California bears a disproportionate share of the TB burden in the U.S. In 2019, there were 2,113 TB cases in California, 24% of all cases nationally despite having 12% of the U.S. population [4, 5]. Of Californian TB cases, 84% occur among persons born outside the United States and rates of tuberculosis among non-US-born Asians are 50 times that among US-born whites [6].”

A conceptual framework for why each of these data fields from CHIS were chose would also be helpful, especially for readers not as familiar with the domestic TB literature.

�  Revised to clarify connection between health utilization and tuberculosis : “To make progress against TB in California, the number of persons that are tested and treated for LTBI needs to be substantially increased. Recent mathematical models support the scale-up of targeted testing and treatment of non-U.S.-born persons for TB infection as important for the reduction of TB in California [8, 9]. However, these TB prevention activities rely on access and use of healthcare and our knowledge of these attributes among non-U.S.-born persons is incomplete. In California and elsewhere, public health programs are engaging with community groups especially those focused on healthcare and representing affected communities but more information is needed about the demographics, healthcare utilization and potential barriers to care of populations at-risk for TB [10, 11]. Recent studies have highlighted disparities in healthcare utilization among minority groups but have not focused on non-U.S.-born persons at-risk for TB [12, 13]. Understanding healthcare utilization of at-risk populations is important for the planning of TB prevention activities.

Please specify in Methods why you focus on 5 countries named (assuming based on country of origin for most TB cases in CA?).

We revised the methods section to address this comment: “We calculated survey proportions and 95% confidence intervals (CI) stratified by country of birth, focusing on the six countries with the highest number of TB cases in California, specifically Mexico, United States, Philippines, Vietnam, China, and India. These countries accounted for 80% of all cases in California during 2016-2017 [18, 19].”

Suggest a citation for this statement as it forms a key underlying premise for the purpose of the paper (ln 67)” One specific barrier to implementing TB prevention in large health systems is that country of 68 birth, the most important risk factor for TB, is often not captured in the electronic medical 69 record (EMR).”

Citation added.

This statement does not seem to make sense (ln 277-278) “Our results show that non-English language at medical visit was an excellent proxy for non-U.S. 278 birth, but identified only half of all non-U.S.-born persons.” How is a proxy excellent if it only identifies half of the eligible population? Please refer to the 2-way table you present in results as to how you would like the reader to interpret this statement. Are you say that the positive predictive value or specificity is high but sensitivity is low? If so, please state as such.

Agreed. We have revised the language toclarify: “Fifth, persons who used a language other than English at their medical visit were highly likely to be born outside the U.S. Thus, preferred language may be suitable as a starting point for identifying high-risk subgroups. However, non-English language at medical visit identified only half of all non-U.S.-born persons.”

We also mention high specificity and low sensitivity in the results section: “As a proxy for nativity, language at medical visit had a low sensitivity (42%) and a high specificity (99%) (table 3).” Please note the table numbering has changed for tables 3 and 4.

Please describe important limitations of using CHIS data, ie, sampling bias based on phone and self-response and how this may actually underestimate the prevalence of some of those key sociodemographic determinants that affect TB care.

Agreed. The following text was added to the limitation section: “The survey was conducted by phone and may under-represent persons who are less likely to answer the phone, such as persons experiencing homelessness, young adults, and non-English speakers. Furthermore, it relies on participant self-report which may underestimate key determinants of TB risk, such as poverty and country of origin, because of social desirability bias.”

Table 3 is challenging to read and interpret. Suggest revising.

Agreed. We have simplified the table by splitting it into two parts and relegating one part to the supplement. The table is now table 4 and Supplement Table 1.

You may want to consider using the first paragraph of the Discussion as the last paragraph of the Introduction, as it is the first place that seems to clearly articulate the purpose for the analysis presented.

Yes, very helpful suggestion. We have moved the first paragraph of the discussion to the end of the introduction.

Reviewer #3:

This is an interesting paper. It has the potential benefits in the field of TB in the USA. But to let it be strong enough, some clarifications are needed. Below are some suggestions which could help improve the paper if the authors found them relevant.

- I would suggest to further explain the methodology. I’m a little bit concerned with the methodology section as presented. The methods section should be clearly and unambiguously stated. I find that there are many references that are indicated and that unfortunately hide a lot of details. For example, the methodology does not show the countries or let's say the different nationalities (India, Mexico, USA, Philippine, Vietnam, etc.) mentioned in the results section. Is there any link or relationship between individuals regarding their nationalities and the risk to get TB? Also, what is the threshold and the criteria of poverty according to the place of birth? According to the fact that poverty in the US could be completely different of the one in Philippine or somewhere else…

We have revised the methods section to address these concerns. With regard to countries of origin we have included the following text: “We calculated survey proportions and 95% confidence intervals (CI) stratified by country of birth, focusing on the six countries with the highest number of TB cases in California, specifically Mexico, United States, Philippines, Vietnam, China, and India. These countries accounted for 62% of all cases in California during 2016-2017 [14, 15].”

In reference to poverty, we added this language: “Poverty was defined as less than 139% of the U.S. federal poverty level. The respondent’s percentage of federal poverty level was calculated using household income earned in the U.S. and household size.”

- HMO. I don’t know what this acronym means! Please put the definition in bracket (p.99)

Apologies for this oversight! We have included the full wording now in the methods section: “Usual source of care was condensed from seven categories to three as follows: doctor’s office, health maintenance organization (HMO) or Kaiser were grouped as doctor’s office…”

- In most of the items presented in the results section, it is not easy to perceive the link between the different factors (diabetes, smoking, good or bad health, etc.) mentioned and their relationship with TB. The authors should discuss this further.

Revised the discussion to clarify the link between risk factors and tuberculosis. Here’s the passage from the discussion section: “Third, risk factors for the progression of latent TB infection to TB disease varied widely among the populations examined. Diabetes and smoking are associated with increased risk of progression of latent TB infection to active TB disease [23, 24]. Self-reported diabetes among Philippines-born and Mexican-born persons was more than double the rates for persons born in other countries including the U.S., similar to prior work [25, 26]. Likewise, former smoking was twice as high among Philippines-born and Mexican-born persons than among persons born in China, India or Vietnam as has been previously documented [27, 28]. The prevalence of these risk factors among populations already at risk for TB provides opportunities for engagement with providers who may not currently think about TB even when seeing persons at risk for the disease.” We also add the following text to the methods section “Smoking and diabetes were considered because they are risk factors for progression of latent TB infection to TB disease [20, 21].”

- The discussion section, as presented, in my opinion is more a part where the authors interpret their results and not discussing them. The discussion, as its name indicates, should be the place where the results, while being interpreted, are also confronted with the studies of other authors and where the points of view are clearly confirmed, refuted or nuanced. And this should be felt in the richness of the references mentioned in the said section. But, as we can see here, the authors have mentioned only 2 references in this whole long discussion... And besides, the article is not rich enough in terms of bibliographic references. So, I suggest to enrich it further, if only with a little more reading...

We a revised the discussion to juxtapose our results with results from the literature and have now included nine references in this section.

- Where is the conclusion section? And what are the main conclusions of the data obtained from the California Health Interview survey (CHIS)?

We have added a conclusion section: “Our analysis points out several important differences in demography, healthcare access and utilization, and language use among populations at risk for TB by country of birth. These differences present opportunities and signal potential pitfalls for planning outreach to specific communities at risk for TB and the providers, clinic systems, health insurers and health insurance purchasers who serve them.”

- What could be the concrete added value of this article? What contribution and especially how can the results obtained contribute to the elimination of TB in the whole USA in general or at least in California more specifically? This is not clear in the paper.

We have include extra language on the concrete value added of this article in the conclusion: “These data could be used to inform public awareness campaigns, provider education, academic detailing, and community outreach efforts. We envision these efforts will be multi-faceted, multi-sectorial, and adapted to specific communities and providers and that they include input from populations at risk for TB. While the information here most directly supports this tailored approach in California, we believe that similarly crafted approaches would help elimination TB in other states and across the U.S.”

Submitted filename: PLOS ONE - revisions and responses v2.docx

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1 Nov 2021

Submitted filename: Demography pop at-risk for TB - clean.docx

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19 Nov 2021

Second Revision - Response to Reviewers:

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Reviewer #4: All comments are included in the attachment review report, the authors are particularly recommended to give adequate attention revising the manuscript for coherence of ideas and some areas need further clarification. For instance abstract.

We have complete extensive revisions to improve the coherence of ideas and clarify areas of the manuscript that were muddled, especially the abstract. I have included the point by point comments and responses here, but it may be more convenient for the reviewer to view them in context in the track changes version of the manuscript which has been uploaded as part of this submission.

Title: “unncessary authors can discuss about demographics under the health care utilization title-----"

Revised per request. Modified text to avoid stigmatizing language

Title: “I have searched to know who are popln at risk but nowhere the authors deined “

Very good point. I have included the definition in the methods section (line 109) and revised the introduction to highlight these groups (line 58).

Comment on short title: “not sure whether this is important”

Submissions require short title under 100 characters

Comment on abstract methods: “very much shallow make it has to be detail”

Made revisions here to provide more detail on the methods.

Comment on abstract methods language which recapitulated old mansucript title: “not clear how relevant”

Deleted reference to language use here. The relevance is discussed in the manuscript

Comment on abstract conclusion: “better conculusion”

Revised the conclusion to highlight an important finding which was that populations who experience risk for TB had health insurance and used healthcare.

Line 100: “why?”

Modified language to explain why adult survey was used.

Methods, Line 104: “very large pargraph better to make short and clear paragraphs”

moved to appropriate subsection below.

Line it is better if the authors descibe each methodology scetion separately

Agreed. Added subsection headers and re-arranged text to fit into subsections.

Methods: “this seems operational definition of terms,I think authors need to have operational definition section”

Agreed. Add subsection headers and re-arranged text to fit into subsections.

Results: “I think authors are not following plos one author guide for writing tables and graphs”

I have reviewed the table requirements and I believe that all tables in this document comply with the author guidelines. Can the reviewer or editor please specify what about the tables does not follow journal style guidelines?

Results section, health insurance subsection: “how do authors corrplate health insurance with utilization of health service;healthcare financing vs utilization. is it this is not out of the scope of this study”

The focus of the paper is on the differences in health utilization between populations who experience risk for TB. Health insurance is a key component of healthcare access, but alone it does not ensure utilization. That is why we looked at both health insurance and healthcare utilization. Again, our interest was to ¬understand if these populations had different insurance or utilization levels.

Results section, Overall Health and Risk factors for TB reactivation subsection: “journal requirment”

As above, apologies, I am unclear as to what does not meet the journal style requirement here. Can you specify what I can do to bring this in to compliance with journal style guidelines?

Table 3: “such descriptions are expected in testing new tests and gold standard test in epidemiology why authors included here, not clear”

In the introduction, we discussed that country of birth, a key risk factor for TB, was missing in many EHRs but that preferred language was used as a proxy. Here, we are setting up results for the use of language at medical visit as a method for identifying persons born outside the U.S. We thought that the standard calculations on sensitivity and specificity would be help readers understand how language could be used to identify non-U.S.-born. We draw conclusions from these results in the discussion (line 341). We have added language in discussion to further clarify the use of language as a proxy.

Discussion: “what will be the recommendation of the authors for this result;aganist health insurance”

Apologies, I’m not sure I fully understand the comment. The result that most persons who experienced risk for TB had health insurance is a positive one, in that, it suggests that having health insurance is not a barrier to accessing healthcare for many in these populations. We highlight the importance in line 291 “With the notable exceptions of persons experiencing homelessness and one quarter of persons born in Mexico who are uninsured, the hurdle of getting at-risk populations into care has largely been met.” We are certainly not recommending against health insurance. Perhaps the reviewer could further explain?

Acknowledgements: “many of the jouranl requrements are not fullfilled”

As above, apologies, but after reading through the journal requirements again, I am unsure as to what about the tables and table references is not in compliance with journal requirements. Could you specify what in particular about the tables and table references does not meet journal requirements?

Submitted filename: Response to reviewers.docx

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13 Jan 2022

16 Mar 2022

Response to Reviewers:

Reviewer #6: Tuberculosis (TB) is the disease that should be paid attention as one of the re-emerging infectious ones. The authors concluded that analysis of CHIS provided several important differences by country of birth and language for planning outreach, public awareness campaigns, and provider education etc.

This paper told the case of California, however, information from this would be useful in states with many emigrants for controlling the occurrence of TB and other infectious diseases.

The title should reflect the conclusion to some extent.

Thanks for this comment. We believe that this analysis has implications for TB elimination in other states and may potentially be helpful for the control of other disease of public health interest. However, given that these data are focus solely on California and these populations where chosen because they experience a higher risk of TB, we think that the title as it stands reflects the scope of the data well.

Reviewer #7: They presented well and followed most of the guidlines, but you need to improve standard english for a scientific research work.

We have made changes throughout the manuscript to clarify language. We have added Oxford commas throughout and simplified language in multiple passages.

Reviewer #8: General comments:

As the article defines being born overseas (in high TB risk countries) as the main risk factor for TB why are US-born people included (or are they the comparison group and if so why not also include other low TB countries)?

We revised the methods section to address this question. The language is as follows:

“We chose to examine health insurance, healthcare utilization and language use among persons born in Mexico, the United States, the Philippines, Vietnam, China, and India. When stratifying by country of birth, these six countries had the highest number of TB cases in California. Together they accounted for 80% of all cases in California during 2016-2017. Thus, for the purposes of this analysis, we defined populations who experience risk of TB as persons born in these six countries.”

I though the aim of the paper was to identify how health insurance, healthcare utilization and language use impact on those at risk of TB and yet no comparison analysis was conducted (adjusting for confounders).

Thank you for this comment. It indicates that we have not adequately laid out the aim of this analysis. The aim is not to assess the impact of health insurance and other factors on the risk of TB but rather to describe health insurance and other factors such that we can better plan TB interventions. With this in mind, we revised the final paragraph of the introduction to read:

“Our aim was to describe the health insurance, healthcare utilization and language use of groups that experience risk for TB in California using a large-scale, population-based health survey to inform planning of TB prevention activities. As California transitions from TB control activities focused on finding and treating active TB disease to TB prevention activities requiring latent tuberculosis infection (LTBI) testing and treatment among populations who experience risk for TB, detailed knowledge about the population of the ten million persons in California born outside the U.S. is crucial.”

There is no description of the statistical methods used for the descriptive comparisons and it appears that no models were developed.

The statistical methods for the descriptive comparisons are laid out in the Method section under statistical analysis. I have provided an excerpt here.

“We calculated survey proportions and 95% confidence intervals (CI) stratified by country of birth. We adjusted the following variables by age: doctor’s visit in the last 12 months, overall health, smoking and diabetes. We used the 2017 U.S. Census annual estimate of population for California as the standard population [22].”

With regard to the development of models, we believe that descriptive analysis is sufficient to complete the main aim. We were interested in understanding the health insurance coverage, health utilization and language use of these populations which have a fairly high risk of TB such that public health programs can plan to engage these populations more efficiently. For example, if programs were planning printed flyers to engage persons born in the Philippines, they might reasonably use some flyers printed in English and print a limited number of flyers in Tagalog based on the fact that 93% speak English well, very well or only speak English. In contrast, when planning flyers for persons born in Vietnam, they might reasonably print more flyers in Vietnamese as 53% of this population speaks English not well or not at all. We outline this point in our conclusion excerpted below:

“Our analysis points out several important differences by country of birth in demography, healthcare utilization, and language use among populations who experience risk for TB. These differences present opportunities and signal potential pitfalls for planning outreach to specific communities that experience risk for TB and the providers, clinic systems, health insurers and health insurance purchasers who serve them. These data could be used to inform public awareness campaigns, provider education, academic detailing, and community outreach efforts.”

The tables on language at consultation and by country does not add much to the paper as apart from providing the % of the population who also speak English.

We outlined the use of language at medical visit as potentially a reasonable substitute for the main risk factor for TB in the U.S., country of birth, which is often missing in medical records. From the point of view of a public health program considering ways to increase appropriate TB testing, we view this result as one of the most useful in the manuscript.

“One specific barrier to implementing TB prevention is that country of birth, the most important risk factor for TB, is often not captured in the electronic medical record (EMR) [16]. Without country of birth data, technology available in the EMR, such as prompts or reflex testing, cannot be used to promote TB testing among these at-risk groups. Preferred language at medical visit, which is often populated in EMR data, may be useful as a proxy for country of birth.”

We also argue for the usefulness of our results in the discussion:

“Fifth, we investigated whether language at medical visit could be used to identify persons born outside the U.S. We found that persons who used a language other than English at their medical visit were highly likely to be born outside the U.S. Thus, preferred language may be suitable as a starting point for identifying high-risk subgroups.”

Because of the limited analysis, including no confounder adjustments, the conclusions are limited and not very informative.

In order for the article to be informative the aims, definitions and analysis needs to be reconsidered.

It is true that we did not build multivariable models or make adjustments for confounders. The aims of this analysis were to describe health insurance, health utilization and language use among populations that experience risk for TB. These pieces of information are crucial to progressing toward TB elimination. From the conclusion:

“These differences present opportunities and signal potential pitfalls for planning outreach to specific communities that experience risk for TB and the providers, clinic systems, health insurers and health insurance purchasers who serve them. These data could be used to inform public awareness campaigns, provider education, academic detailing, and community outreach efforts.

Our aim was not to predict an outcome or to provide evidence of causation between an exposure and outcome. Thus, we did not use multivariable models. But considering the aim of the analysis (which we have clarified in responses above), those methods did not seem to us to fit the job. The conclusions are simple but we do not think they are limited. One quarter of California’s population was born outside the United States. That’s 10 million people. If we can understand the health insurance coverage, health utilization and language use of persons born in these six countries, we have started to understand how we can engage these populations and hopefully bring some TB and other diseases that affect some of these populations.

9 May 2022

Health insurance, healthcare utilization and language use among populations who experience risk for tuberculosis, California 2014-2017.

PONE-D-21-08860R3

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Reviewer #6: All comments have been addressed

Reviewer #7: All comments have been addressed

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Reviewer #6: The manuscript has been adequately revised.

The content of this study is interesting, and the information obtained from this would be reflect 険the health administration in California and also in the United States.

Reviewer #7: I see that most of previous reviews whether my comments or that from other reviewers' were addressed.

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Reviewer #6: Yes: Shinichi Arakawa

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16 May 2022

PONE-D-21-08860R3

Health insurance, healthcare utilization and language use among populations who experience risk for tuberculosis, California 2014-2017.

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