Hypertension in the eastern province of saudi arabia: results of a screening campaign.

OBJECTIVE: To estimate the prevalence of hypertension through a screening campaign in the Eastern Province of Saudi Arabia, and examine its association with lifestyle factors. RESEARCH DESIGN AND METHODS: In 2004, all Saudi residents in the Eastern Province, aged 30 years and above were invited to participate in a screening campaign for the early detection of diabetes and hypertension. Blood pressure was recorded by trained nurses using a mercury sphygmomanometer, based on the recommendations of (JNC- VII). A positive screening test for hypertension was defined as systolic and/or diastolic blood pressure of ≥ 140 and 90 mm Hg, respectively. Subjects who had positive screening tests were asked to come on the following day for a confirmation of the reading. Hypertension was considered if there was a persistent reading of systolic and/or diastolic blood pressure of ≥ 140 and 90 mmHg after confirmation, or when there was history of a previous diagnosis.
RESULTS: 21% of the sample was positive from previous history or screening. After confirmation, the prevalence of hypertension dropped to 15.6%, pre-hypertension was 3.7%, whereas the prevalence of undiagnosed hypertension was 2.8%. The prevalence rose with age. It was higher in women than in men of all age groups and in all sectors of the eastern province, although the mean systolic and diastolic BP was higher in men than women. It was higher with lower education, in widows and divorcees than others (P<0.0001).
CONCLUSION: The yield of the screening for abnormal blood pressure was high. Systematic follow-up of subjects with abnormal screening results is vital.

INTRODUCTION

Screening for high blood pressure in adults is recommended by different organizations,1–3 and the rationale for these recommendations is supported by strong evidence.4 Hypertension is considered a main component of cardiovascular disease risk, in addition to its important adverse health outcome.5 It is a widely prevalent disease; The World Health Organization (WHO) has estimated that hypertension causes one in every eight deaths. Globally, there are four million people who die annually as a direct result of high blood pressure6 and it is estimated there would be an increase of hypertensives to 1.2 billion by 2010.7 In the Eastern Mediterranean Regional Office (EMRO), hypertension has reached 26%.8 In Saudi Arabia, hypertension has become an increasingly important health problem affecting a large number of Saudi people,9 which has necessitated early detection and management as a priority through screening programs. The potential benefit of early intervention for high blood pressure supports the importance of screening and follow-up of abnormal screening results. Several studies have demonstrated the rule of halves, whereby half of those affected are detected, half of those detected are treated and half of those treated are adequately controlled,10 although it is questionable whether this works.11 Because hypertension is asymptomatic most of the time, the benefit of early detection and treatment is proven,12 and it is cost effective.13 Accordingly, the General Directorate of Health Affairs in the eastern province, in collaboration with the directorate of primary health centers, organized a community-based screening campaign program aimed at studying and improving the care of hypertensive patients through the primary health care system, through identification of undiagnosed cases, and the offer of effective management as one of its objectives. This study was conducted to measure the prevalence of hypertension through a screening campaign in the Eastern Province of Saudi Arabia, and examine the associations with socio-demographic factors.

METHODS

The study was part of a screening campaign for diabetes and hypertension conducted between 28 August 2004 and 18 February 2005. Details of the methodology used were described previously.14 A scientific committee formulated the detailed process to carry out this campaign. This included the determination of the standards for running the campaign, accreditations of instruments and health education materials to be used, besides training, financial, supervision and health education committees, data processing and entry committees. A media campaign was organized in each sector using written materials and audiovisual media, as well as posters that were put on billboards along the streets and in other public places in the Eastern Province. The target population was 650,000 subjects. All Saudi residents in the Eastern Province of Saudi Arabia, aged 30 years and above were invited to participate in a screening campaign for the early detection of diabetes mellitus (DM) and hypertension at more than 300 examination posts, data collection centers, set up in all primary health care centers, governmental, and most private hospitals and dispensaries, in addition to mobile teams, and other venues. The Eastern Province was divided into 15 sectors as follows: Dammam, Khobar, Qatif, Ras Tanura, Abqaiq, Safwa, Jubail, Khafji, Oraiera, Nuaeria, Sarar, Qaria Olaya, Rafia, Hassa, and Hafr Al-Baten. A structured questionnaire developed through a focused group, and validated by experts in the fields of DM and hypertension, was used by pre-trained health teams, who had attended a training course for the conduct of the campaign, to obtain information on health status and lifestyle. The participants’ weight, height, and blood pressure were measured. Based on the recommendations of The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC-VII)15 blood pressure was measured twice for each participants at rest, in the sitting position, at an interval of 1-2 minutes. The mean of the two readings was recorded. If the difference between the two readings was greater than 5 mmHg, measurements were retaken until the reading were stable. Blood pressure measurement was taken, using a standardized mercury sphygmomanometer, with an appropriate-size cuff inflated to a pressure approximately 30 mmHg greater than systolic. The patient's arm was maintained at the level of the heart. The systolic pressure was considered as equal to the pressure at which the pulse is first heard by auscultation (Korotkoff phase I), and the diastolic pressure as equal to phase V (the point of disappearance of the sound). The screening test was considered positive if the systolic and diastolic blood pressure was ≥ 140 and /or ≥ 90 mmHg, respectively.

The diagnosis of hypertension was made if a positive screening was confirmed on a subsequent day, or if there was a history of previous diagnosis, irrespective of the blood pressure reading. Pre-hypertension was defined as systolic and diastolic of 120-139, and /or 80-89mmHg, respectively.

Co-coordinators were assigned for each sector to supervise the examination posts, ensure the continuity of work and calibration of equipment and resolve issues such as absence of health workers, equipment breakdown, shortage of forms, proper completion of all forms, reminders to defaulters, ensure the follow-up of campaign letters and cooperation with coordinators in other sectors and main supervision committees.

The forms were collected from each sector, where they were double-checked for completeness. Non-eligible people were excluded, and forms with incomplete data, or unconfirmed results were sent back to the sectors with a covering letter asking for corrections to be made.

All analyses were performed using SPSS version 15. The significance of univariate difference analysis was assessed using chi-squared test for categorical variables, and t-test, ANOVA for systolic and diastolic variable with gender and categorical age respectively.

Those variables found to be significantly associated with hypertension were included in multiple regression analysis, using men and women, separately, with BP as the dependent variable, and age, sector, marital status, education, occupation as independent variables. The odds ratio and 95% confidence interval were calculated, and a p value < 0.05 was considered as indicative of statistical significance.

RESULTS

Of the 650.000 eligible individuals targeted by this campaign, 214,381 participated forming 33%. Data on 197,681 were available. The mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) of the participants was (mean ± standard deviation) 121.04±15.84 and 77.59±9.20 mmHg, respectively. The mean SBP and DBP of the second reading after confirmation of the screened positive was 127.71±16.75 and 80.97 ±9.67mmHg. The screened mean systolic and diastolic BP was significantly higher in men than women 122±14 and 78±8.7 and 119.8±17 and 76.6±9.5 mm Hg, respectively; (p<0.001). On the other hand, it was also significantly higher in males than females after confirmation of screened positive individuals 128+15.0 and 82+9.0 and 126.9+17.0 and 80+9.5 mmHg, respectively (p<0.001). Both the mean systolic BP and diastolic BP increased with age, reaching their peak in the age group, 50-59 in both genders (p<0.0001). This pattern was seen in the screening and in the confirmation of screened positive (p<0.0001).

Regarding individuals who had not been diagnosed previously, 15,390 (9%) were screened positive for hypertension, 7,308 (47.5%) of whom had the confirmation test for blood pressure. The rest refused to return, failed to attend the referral, or could not be traced.

The overall prevalence of hypertension, from screening, was 41,584 (21%) which dropped to 30,706 (15.6%) in the second reading. However, the overall prevalence of pre-hypertension was 7,323 (3.7%). Newly diagnosed hypertension was 4,330 (2.8%) Hypertension was more prevalent in women (18.1%) than in men (13.1%) with p-value <0.0001 (Table 1).

Table 1

Prevalence of hypertension and pre-hypertension

Table 2 displays the prevalence of hypertension in relation to demographic characteristics. The prevalence of hypertension showed an increase with increasing age (p<0.0001).

Table 2

Prevalence of hypertension in relation to age and marital status

Regarding marital status, hypertension was significantly more prevalent among widowed males and females (29.9%, 44.7%), followed by divorced males and females (16.9%, 21.5%), respectively, and was lowest among single individuals (p<0.0001).

The prevalence of hypertension was significantly higher with lower income, and low educational level (p <0.0001). Among females, the highest rate of hypertension was in housewives (20.6%) and the lowest among professionals (6.8%) (p<0.0001). Among men, the highest rate was in the unemployed (30.4%) and the lowest was in military personnel (7%) with p-value <0.0001 (Table 3).

Table 3

Prevalence of hypertension in relation to socioeconomic variables

Regarding geographical distribution, the prevalence of hypertension, among men, was higher in subjects living in Oraiera (26.3%) and lowest was in Jubail 6.5% (p<0.005). Among the women, the highest rate of hypertension was in Al-Hassa (22.8%) and was lowest in Jubail with 11.3% (Table 4).

Table 4

Prevalence of hypertension in relation to geographical distribution

Logistic regression analysis was used to quantify the effect of socioeconomic factors with hypertension as a dependent factor (Table 5). The analysis indicated that increasing age, being married, widowed, or divorced, were significant predictors of hypertension in men and women; whereas being in the military service, being a professional, technical, non-technical, employed in administration, and those with higher education starting from secondary school were conversely associated with hypertension in men. In women, there was negative association with education. But being professional, technical, an employee in the administrative sector, housewives, and unemployed were significant predictors of hypertension. Having a higher income was significantly associated with hypertension in men, but not in women.

Table 5

Multiple logistic regression models of variables associated with prevalence of hypertension

DISCUSSION

Our study is unique in two ways. First, it involved a large number of participants. Secondly, the follow-up of screened positive readings added to its merit. A comparison of the different surveys of blood pressure distribution in Saudi Arabia91617 is difficult as the cut-off point (ranging from systolic BP of 140 to 160 mmHg), and characteristics of population varied substantially. Generally, these studies have shown a high and rising prevalence of hypertension. A study done within a comparable time cited a prevalence similar to ours.17 However, our figure is more realistic since it was obtained after the confirmation of positive screening. For example, in our study, confirmation of the BP reading reduced the prevalence figure from 21% to 15.6%, and the drop was statistically different even in sectors with almost 100% follow-up of screened positive results like Oraiera and Hafr-Al-Baten. This variability may be attributable to a “white-coat” effect causing a temporary increase in BP.18 Hypertension is a complex multi-factorial and polygenic disorder that is thought to result from an interaction between an individual's genetic make-up and various environmental factors,19 which may explain the variability of hypertension among sub-populations within the eastern province. The current study showed that the prevalence rates of hypertension in Oraiera were higher than those in other sectors, while it was lowest in Jubail. The reason for this could not be determined from this campaign. Jubail is an industrial city with a dominant young working population, which may explain the relatively lower prevalence of hypertension those in comparison with other sectors.

An apparently higher prevalence of hypertension was found in women than men in univariate analysis, although the average SBP and DBP was higher in men than women. This finding was consistent in sub-classification of all age groups, marital status, in most sectors, except Oraiera, but showed a low prevalence with high education, higher income, and professional occupations in women than men.

The rate of age-related blood pressure increase and SBP was observed with increasing age, whereas DBP peaked at the age group 50-59 years. This observation, documented previously, was explained by a wide pulse pressure in the elderly.20

In such a large campaign, there could be bias from different response rates in different sectors.14 However, the strength of this study is that the large sample sizes was able to provide a nationally fair representative estimate of hypertension in the Eastern Province of Saudi Arabia. Besides, the percentage of our participants was consistent with the latest census on age and gender done in the Eastern Province of Saudi Arabia.21

Generally, the overall yield of screened individuals with newly diagnosed hypertension was high, which indicates a strong recommendation for blood pressure screening to detect undiagnosed cases. Lack of follow-up was associated with both health team factors (failure of referral), and patient factors (failure to keep scheduled follow-up). On other hand, psychological factors may have played a role since the newly screened positive subjects could have been in a state of denial with regard to their high blood pressure.

CONCLUSIONS

The yield of this screening campaign has proved that the prevalence of hypertension may be higher than it appears, which is an indication that it is vital for more screening campaigns to be carried out and as systematic follow-up conducted for subjects with abnormal screening results.