A comparative study of hematological parameters between hypertensive and normotensive individuals in Harar, eastern Ethiopia.

BACKGROUND: Hypertension is the major public health concern; leading to cardiovascular disease. It is associated with alteration in hematological parameters which may lead to end-organ damage. Thus, this study aimed to compare hematological parameters between hypertensive and normotensive adult groups in Harar, eastern Ethiopia.
METHODS: A comparative cross-sectional study was conducted from January to March, 2020 at Jugel and Hiwotfana Specialized University hospital, Harar, eastern Ethiopia. Convenient sampling technique was used to recruit 102 hypertensive patients from the two hospitals and 102 apparently healthy blood donors. Participant's socio-demographic and clinical information were collected using pre-tested structured questionnaire. Blood sample were collected and analyzed by Beckman Coulter DxH 500 analyzer for complete blood count. The data were entered and analyzed using SPSS version 23. Independent t-test and Mann Whitney u-test was used for comparison between groups. Spearman's correlation was used for correlation test. P values less than 0.05 was considered as statistically significant. RESULT: 102 hypertensive and 102 healthy controls were enrolled in this study. The median ± IQR value of white blood cell (WBC) count, hemoglobin (Hgb), hematocrit (HCT), red cell distribution width (RDW) and mean platelet volume (MPV) were significantly higher in hypertensive group compared to apparently healthy control group. Additionally, RBC (red blood cell) count, HCT and RDW showed statistically significant positive correlations with systolic and diastolic blood pressure. WBC count and RDW were significantly and positively correlated with body mass index (BMI). Platelet (PLT) count had a significant but negative correlation (r = -0.219, P = 0.027) with duration of hypertension illness while MPV showed positive and significant correlation (r = 0.255, P = 0.010).
CONCLUSION: The median values of WBC, Hgb, HCT, RDW and MPV were significantly higher in hypertensive patient compared to apparently healthy individuals. Hence, it is important to assess hematological parameters for hypertensive individuals which may help to prevent complications associated with hematological aberrations. However, further studies are required to understand hypertensive associated changes in hematological parameters.

Introduction

Hypertension (HTN) is defined as high blood pressure. Blood pressure is the power of blood exerted to the walls of arteries as the heart pumps blood [1]. Normal range of blood pressure is defined as, <120mmHg for systolic blood pressure (SBP) and <80 mmHg for diastolic blood pressure (DBP). Hypertension is a reading of SBP ≥140 mmHg and/or DBP ≥90 mmHg [2]. The pathophysiology of hypertension is unknown. In about 95–97% of hypertension cases, the cause is unknown and its characterized as primary hypertension. In the remaining small percent, an underlying disease is responsible for the raised blood pressure [3].

Often times, hypertension shows no symptoms until it has done substantial damage to the cardiovascular system. Thus, its often referred as “silent killer” [4]. A high blood pressure could result blood vessels to develop bulges and create weak spots; which makes it to collapse and burst. If left uncontrolled, hypertension could cause a heart attack, kidney failure, stroke and sometimes death [5].

The cellular components of blood contribute to the viscosity, volume and coagulability of the blood; thus, playing a vital role in regulating blood pressure [6]. Hypertension can alter hematological parameters of the body, leading to functional disturbances in many systems of the body. It causes an increase in WBC count, a decrease in red cell deformability and an increase in platelet activation [7-9]. This alteration may worsen in the microcirculation and enhance an end-organ damage [10].

Hypertension is the leading cause of cardiovascular disease (CVD) and premature death worldwide. 1.13 billion people are affected by HTN worldwide [11]. Though, hypertension is a preventable and modifiable risk factor of CVD, its prevention and control has not yet received appropriate attention in many developing countries [12]. Ethiopia is one of the lower income countries that is troubled by double burden of the diseases. A surveillance in Addis Ababa reported that, 51% of all deaths were due to non-communicable disease, of which, CVD accounts for 24% and hypertension was responsible for 12% of the CVD deaths [13].

Many recent guidelines on the diagnosis and management of hypertension emphasis that, total risk of cardiovascular disease should be quantified so that the type and intensity of treatment can be personalized to the degree of overall risk rather than the level of blood pressure (BP) elevation alone [14]. So, identifying patients with high risk of developing cardiovascular disease (CVD) will enable for early administration of hypertensive treatment and thus, reduce the progression of silent vascular damage [15].

There has been a detailed study of the relationship between high blood pressure and biochemical risk factors, like lipid profile association with hypertension and CVD [6]. However, the definitive pathophysiologic mechanism of hypertension involving hematological parameters is not clearly understood.

While some research has been carried out to investigate the relationship between hematological parameters and hypertension, there is still a broad variation in hematological profile of hypertensive patients between different researches worldwide. Moreover, there are only a few studies conducted on hematological parameters of hypertensive patients in Ethiopia. Studies have shown hypertension related changes in hematological parameters and investigation of these parameters might help for earlier identification and timely management and monitoring of hypertension related complication such as cardiovascular disease. Thus, routinely available and inexpensive hematological test such as complete blood count (CBC) will enable the physician for periodic assessment of the patient conditions and early intervention. So, this study aimed to compare hematological parameters between hypertensive patients and apparently healthy normotensive individuals.

Material and methods

Study design, setting and population

A comparative cross-sectional study design was conducted from January to March, 2020 in two public hospitals; Hiwotfana Specialized University hospital (HFSUH) and Jugel hospital, Harar, Eastern Ethiopia. HFSUH is located in Harar town, 527 kilometer east of Addis Ababa, the capital city of Ethiopia [16]. The hospital is a tertiary referral hospital affiliated with the College of Health and Medical Sciences of Haramaya University, Ethiopia. It is the major referral hospital in the eastern part of the country serving a catchment area with a population close to 3 million [17]. Jugel Hospital is a regional general hospital found in the same town and run by the Harari Regional Health Bureau.

A total of 204 (102 confirmed hypertensive patients and 102 apparently healthy blood donors) study participants were recruited using convenient sampling method, meaning that after reviewing their medical records as well as in depth face to-face interview with the participant, only those who fulfilled the eligibility criteria and consented to participate were selected. There was a total of 80 and 70 hypertensive patients on follow up in HFSUH and Jugel hospitals, respectively. Thus, we used proportional allocation method to recruit participants from the two hospitals. Accordingly, 54 and 48 patients were selected from HFSUH and Jugel hospital, respectively. A study participant with hypertensive and healthy control group were age and sex matched. At Harar blood bank, donors who were screened for transfusion transmitted infectious disease and other chronic diseases and found their blood to be safe for transfusion and gave their consent were recruited and considered as control (normotensive) group. Hypertensive patients having a history of infectious and chronic disease, alcohol consumers, smokers, patients taking antibiotic, treatment for anemia, patients with systemic diseases, pregnant woman and those with secondary hypertension were excluded.

Data collection procedure

Before the data collection, written informed consent was obtained from each participant. In-depth interview using structured questionnaire and review of medical records was used to obtain socio-demographic and clinical data of participant. Prior to the actual data collection, the questionnaire which designed in English was translated into local language (Afan Oromo and Amharic) to obtain more reliable data. The questionnaire was pretested among non-participants at the study site to test its validity. A 3 ml of venous blood was collected from participants by qualified phlebotomist and the sample was run in hospital laboratory by qualified laboratory professional. Blood pressure measurement and anthropometric data such as height and weight were also collected from each participant.

Blood pressure and anthropometric measurement

The data regarding anthropometric variables such as height (to the nearest centimeter without shoes) and weight (to the nearest 0.1 kg) was collected and BMI was calculated as weight in kilograms divided by height in meter squared. Blood pressure was measured by qualified personnel (nurse) using analog sphygmomanometer and stethoscope. For blood pressure determination, measurement was taken twice and average value was used.

Laboratory analysis

A 3 ml venous blood was collected from each participant by experienced phlebotomist and the sample was analyzed immediately by Beckman Coulter DxH 500 hematology analyzer for complete blood count. WBC count, red blood cell parameters (Hgb, HCT, MCV, MCH, MCHC, RDW) and platelet parameters (PLT count, MPV, PDW) were obtained from each sample.

Data quality assurance

The sample was collected and analyzed by qualified laboratory professional by strictly following standard operation procedures. In addition, three level (low, normal and high) commercially prepared control materials were used daily. Completeness and reliability of the data was properly checked and result were reviewed and properly documented.

Operational definition

Hypertension

Hypertension is defined as systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg.

Pre hypertension

Is defined as systolic blood pressure of 120 -139mmHg and or diastolic pressure of 80–89 mmHg.

Stage 1 hypertension

A sub type of hypertension with systolic pressure of 140-159mmHg or diastolic pressure of 90–99 mmHg.

Stage 2 hypertension

Is a subtype of hypertension with systolic pressure of greater than or equal to 160mmHg or diastolic pressure of greater than equal to 100 mmHg [2].

Case

Patient who are confirmed to be hypertensive and on follow up at Jugel and Hiwotfana Specialized University hospital and fulfill the inclusion criteria.

Control

Normotensive apparently healthy screened blood donors at Harar blood bank and fulfill the inclusion criteria.

Statistical analysis

Data was entered and analyzed using SPSS version 23 software. The results are presented using tables. The normality of data distribution was checked by statistical tools of Kolmogorov-Smirnov (K-S). Mean±SD was used for normally distributed data while median with interquartile range for non-parametric data. Comparison of hematological parameters between hypertensive patient and apparently healthy normotensive controls was done with independent t-test for normally distributed data and Mann-Whitney U test for non-parametric data. The correlation of hematological parameters with blood pressure indices (systolic blood pressure, diastolic blood pressure) was assessed by Spearman’s correlation. P value < 0.05 was considered as statistically significant.

Ethical consideration

Ethical clearance was obtained from the department of Research and Ethics Review Committee (DRERC) of Addis Ababa University, College of Health Sciences, department of Medical Laboratory Science and it was in accordance with the principles of the Helsinki II declaration. In addition, an official letter of permission was obtained from the hospitals. Written informed consent was obtained from each participant and confidentiality of the data was assured throughout the process.

Results

Sociodemographic and clinical characteristics of the study participants

The study included 204 study participants that comprise, 102 hypertensive patients with mean age of 51.11 ± 8.4 years and 102 controls with mean age of 48.65 ± 8.85 years. 63 (61.8%) of participants were females in both hypertensive and healthy control groups. The majority of hypertensive patients (85.3%) and control group (83.3%) were urban dwellers. Most of the participants in hypertensive patients, 60 (58.8%) and healthy control group, 48 (47.1%) were married. Regarding educational status, 44 (43.1%) of hypertensive had primary school while 59 (57.9%) of control had up to secondary school.

The mean value of the systolic and diastolic pressure of hypertensive patients were 138.36±16.25 and 85.61 ±9.28, respectively. The mean body mass index of the patients was 24.22 ± 3.93 while it is 23.37 ± 3.57 for control groups. The stage of blood pressure of the patients was also determined and 8.8%, 38.2%, 37.3% and 15.7% were staged as normal, prehypertension, stage 1 and stage 2 respectively (Table 1).

Table 1

Socio-demographic and clinical characteristics of study participants at HFSUH and Jugel Hospitals, Harar, eastern Ethiopia, 2020 (n = 204).

Variables		Hypertensive (n = 102)	Healthy Control (n = 102)
Age	18–35	4(3.9%)	6(4.9%)
	36–55	63(61.8%)	60(59.8%)
	>55	35(34.3%)	36(33.3%)
	Mean ±SD	48.85 ± 8.99	51.1 ± 8.4
Sex	Male	39(38.2%)	39(38.2%)
	Female	63(61.8%)	63(61.8%)
Residence	Urban	87(85.3%)	85(83.3%)
	Rural	15(14.7%)	17(16.7%)
Marital status	Single	7(6.9%)	34(33.3%)
	Married	60(58.8%)	48(47.1%)
	Divorced and widowed	35(35.3%)	20(19.6%)
Educational status	Illiterated	22(21.6%)	12(11.8%)
	Primary (1–8)	44(43.1%)	16(15.7%)
	Secondary (9–12)	28(27.4%)	59(57.9%)
	Diploma and above	8(7.8%)	15(14.7%)
Body mass index	Mean ± SD	24.22 ± 3.93	23.37 ± 3.57
Blood Pressure Indices	Systolic BP (Mean ± SD)	138.36±16. 25	111.03 ± 6.04
	Diastolic BP (Mean ± SD)	85.61 ± 9.28	73.71± 3.75
Stage of blood pressure	Normal	9 (8%)	102 (100%)
	Prehypertension	39(38.2%)
	Stage 1	38(37.3%)
	Stage 2	16(15.7%)
Duration of illness	< 5 years	52(51.0%)
	5–10 years	35(34.3%)
	>10	15(14.7%)

Key: Illiterated = read and write only.

Comparison of hematological parameters among hypertensive and control groups

The normality of the variables was tested and all hematological parameters except platelets were not normally distributed. As result, all variables except platelets are expressed as median plus interquartile range and compared by Manny Whitney test while platelet count is expressed by mean ± SD and tested by independent t test.

The result showed that, there was a statistically significant increase in WBC count, HGB, HCT, RDW and MPV in hypertensive compared to a healthy control group. In contrast, RBC, MCV, MCHC, MCH and PLT showed no statistically significant difference between the two groups (Table 2).

Table 2

Comparison of hematological parameters between hypertensive and apparently healthy control group at HFSUH and Jugel hospital, Harar, eastern Ethiopia, 2020 (n = 204).

Parameters	Hypertensive (n = 102)	Healthy controls(n = 102)	P-value
	Median ± IQR	Median ± IQR
WBC	6.52 ± 3.08	5.29 ± 2.27	0.000
RBC	4.78± 0.79	4.70 ± 0.75	0.055
HCT	42.45 ± 5.42	40.60 ± 4.33	0.001
HGB	14.50 ± 1.93	13.78 ± 2.13	0.027
MCV	88.05± 8.84	88.55 ± 11.98	0.394
MCH	29.80 ± 2.78	30.40 ± 2.03	0.118
MCHC	34.00 ± 1.92	34.35 ± 3.95	0.192
RDW	13.85 ±1.60	13.60 ± 1.55	0.018
RDW SD	43.90 ± 5.30	42.03 ± 2.85	0.063
MPV	9.50 ± 2.22	9.04 ± 1.06	0.024
	Mean ± SD	Mean ± SD
PLT Count	250. 47 ± 75.72	244.99 ± 82.24	0.714

Correlation of hematological parameters with blood pressure indices among hypertensive individuals

A spearman’s correlation was used to assess the relationship between various hematological parameters and the blood pressure indices among hypertensive individuals. The result showed that, there was a significant and weak positive correlation between RBC count and SBP (r = 0.255, P = 0.01) as well as RBC and DBP (r = 0.241, P = 0.015). HCT and RDW also revealed a significant positive correlation with systolic and diastolic blood pressures. The other hematological variables like WBC, MCV, MCHC, MCH, RDW-SD, PLT count, and MPV didn’t show significant correlation with blood pressure indices (Table 3).

Table 3

Correlation of hematological parameters with blood pressure indices among hypertensive individuals at HFSUH and Jugel hospitals, Harar, Eastern Ethiopia, 2020 (n = 204).

Variables	Systolic blood pressure	Diastolic blood pressure
	Correlation coefficient (P-value)	Correlation coefficient (P-value)
WBC	.180 (0.070)	.102 (0.310)
RBC	.255 (0.010) **	.241(0.015) *
HGB	.156 (0.117)	.183(0.065)
HCT	.219 (0.027) *	.354 (0.000) **
MCV	-.162 (0.103)	.030 (0.767)
MCH	.076 (0.450)	.127 (.204)
MCHC	.145(0.147)	.181(0.069)
RDW	.418 (0.000) **	.281(0.004) **
RDW–SD	.186(0.061)	.152 (0.127)
PLT COUNT	—.070 (0.484)	.079 (0.430)
MPV	.046 (0.647)	.098 (0.329)

Key: * = for p-value< 0.05,

** = for p-value < 0.01.

Correlation of hematological parameters with duration of illness and body mass index

Spearman correlation was also done to assess linear relationship between some hematological parameters and body mass index. RDW and WBC count demonstrated a significant but weak positive correlation with BMI. On the other hand, MPV achieved significant positive correlation with duration of illness while PLT count had negative correlation (Table 4).

Table 4

Correlation of hematological parameters with body mass index and duration of illness among hypertensive individuals at HFSUH and Jugel hospitals, Harar, eastern Ethiopia, 2020 (n = 204).

Variables	BMI r (P-value)	Duration of illness r (P-value)
WBC	.208(0.036) *	.155(0.119)
RBC	.114(0.253)	.126(0.206)
HGB	.034(0.736)	.125(0.211)
HCT	.011(0.915)	.060(0.552)
MCV	-.154(0.122)	-.064(0.524)
MCH	.014(0.890)	-.123(0.217)
MCHC	.019(0.850)	-.127(0.205)
RDW	.198(0.046) *	.049(0.622)
RDW–SD	.030(0.763)	-.075(0.455)
PLT COUNT	.190(0.056)	-.219(0.027) *
MPV	-.022(0.828)	.255(0.010) *

Key: * = for p-value< 0.05,

** = for p-value < 0.01, r = correlation coefficient.

Finally, we compared hematological parameters between male control and hypertensive groups, and parameters such as WBC count, MCV and platelet count were normally distributed while the rest of the parameters were not. The finding showed that parameters such as WBC count, MCV, MCH and MCHC were significantly different between the two groups (Table 5).

Table 5

Comparison of hematological parameters between male hypertensive and male control group at HFSUH and Jugel hospital, Harar, Ethiopia, 2020 (n = 78).

Parameters	Hypertensive males (n = 39)	Healthy control males (n = 39)	P value
	Mean ± SD	Mean ± SD
WBC (103/ul)	6.82± 2.02	5.30 ± 1.50	0.013
PLT Count(103/ul)	241.95 ± 67.01	234.25 ± 66.37	0.972
MCV (fl)	89.37± 4.48	86.81± 7.64	0.030
MCH (pg)	30.48± 1.40	31.10± 2.70	0.040
	Median ± IQR	Median ± IQR
HCT (%)	45.10± 7.20	41.80 ± 6.00	0.029
Hgb (g/dl)	15.50 ± 2.60	15.03 ± 2.33	0.404
MCHC(g/dl)	34.7± 1.60	36.2 ± 1.40	0.001
RDW CV (%)	13.80 ±1.40	14.00± 0.90	0.213
RDW SD (fl)	43.20 ± 5.00	42.60 ± 6.30	0.700
MPV (fl)	9.50 ± 2.30	8.80 ± 1.32	0.072
RBC (106/ul)	5.20 ± 0.86	4.89 ± 0.65	0.146

In case of females, only platelet count and RDW CV found to be normally distributed. Significant difference in WBC count, HCT and Hgb were observed bewteen female control and hypertensive group (Table 6).

Table 6

Comparison of hematological parameters between female hypertensive and female control group at HFSUH and Jugel hospital, Harar, Ethiopia, 2020 (n = 78).

Parameters	Hypertensive females (n = 63)	Healthy control females (n = 63)	P-value
	Median ± IQR	Median ± IQR
WBC (103/ul)	6.40 ± 2.62	5.17± 1.97	0.001
RBC count	4.69 ±0.53	4.58 ±0.70	0.104
MCV (fl)	88.10 ±10.70	89.70± 10.80	0.073
MCH (pg)	29.65 ± 3.10	30.30 ± 2.00	0.150
HCT (%)	42.00 ± 4.90	40.00 ± 4.00	0.010
Hgb (g/dl)	14.01 ± 1.60	13.20 ± 1.30	0.012
MCHC(g/dl)	33.40± 1.50	33.30 ± 3.10	0.414
RDW SD (fl)	44.30 ± 5.70	42.03 ± 1.30	0.044
MPV (fl)	9.50 ± 1.35	9.05 ±0.71	0.108
	Mean ± SD	Mean ± SD
PLT Count(103/ul)	255.75 ± 89.71	251.63 ± 90.56	0.439
RDW CV (%)	14.13 ± 1.27	13.20 ±1.31	0.928

Discussion

Hypertension has become the major public health problem in developing countries [12]. In Ethiopia, hypertension related CVD death is increasing [13]. Thus, the need for early identification of patient with risk of cardiovascular disease and timely intervention is vital. So, this study is aimed to compare hematological profile of hypertension patients with apparently healthy individuals as well as to correlate blood pressure indices with hematological parameters.

In this study, the median values of WBC count, Hgb, HCT,RDW and MPV were significantly higher in hypertensive patients compared to apparently healthy control group. In the bivariate correlation analysis, RBC count, HCT and RDW showed positive correlation with blood pressure indices. RDW and WBC count also achieved significant positive correlation with BMI. On the other hand, duration of hypertension was positively and negatively correlated with MPV and PLT count, respectively.

Our finding showed that hypertensive group had significantly higher median ± IQR value of WBC count (6.52 ± 3.08) compared to the control group (5.29 ±2.27). The finding is in agreement with Enawegaw et al. [18], Babu et al. [15], Al muhana et al. [19] and Emamian et al. [7]. In contrast to this, another studies by Reis RS et al. [20] and Divya R et al. [21] showed no statistically significant result in WBC count. The increased WBC count in hypertensive patient could be due to the presence of vascular dysfunction in those patients which leads to activation of cytokine system. cytokines such as SCF/c-kit are produced to repair the endothelial injury; participate in differentiation and proliferation of hematopoietic cell [22]. Activated and differentiated leucocytes can produce more cytokines and the increased adherence of the stimulated leukocytes to the vascular endothelium; causing capillary leukocytosis and subsequent increased vascular resistance, thus, causing an increase in blood pressure [23]. Activated WBCs also reflect the inflammatory activity of atherosclerosis that perpetuates vascular injury and tissue ischemia [24].

In the present study, the median± IQR values of Hgb were found to be significantly higher in the hypertensive (14.50±1.93) than in control (13.78±2.13) group. Studies from India [15], Iran [7], Korea [9] and Ethiopia [8] found similar results. In contrast, studies from Brazil [20], Saudi [19] and India [21] Showed contradicting result. The reason behind the increment of Hgb in hypertensive patients are not entirely known; but it might be related to endothelial cell damage and subsequent increased in the concentrations of growth factors [25]. Evidences show that concentration of serum hepatocyte growth factor is positively associated with hypertension and increased Hgb concentration. As growth factors enhance hematopoiesis, which produces erythrocytes, hemoglobin levels may increase with increasing levels of growth factors [26, 27].

In this study, the median± IQR values of HCT were found to be significantly higher in the hypertensive (42.45±5.42) than control (40.60±4.33) group. Previous studies also showed similar results [7, 8, 15, 28]. On the other hand, study by Divya et al. [21] found significantly lower HCT levels in hypertensive patients compared with control group. The possible mechanisms underlying the association between HCT and high blood pressure is that, HCT is a determinant factor for high whole blood viscosity during hypertension [29]. This may lead to a peripheral resistance to blood flow and high blood pressure [30]. Evidences showed that, most hypertensive patients exhibit increased blood viscosity compared with healthy controls. Therefore, high HCT in hypertension could reflect a true increase in red blood cell mass as well as hemoconcentration caused by a reduction in plasma volume [28].

In our study, median ± IQR of RDW increased significantly in hypertensive group (13.90 ± 1.65) than in a healthy control (13.60 ± 1.55) group. This result is in line with studies by Tanindi A. et al. [31] and Gunebakmaz O.et al. [32]. Another study from Iran by Emanain M. et al. [7] reported contradicting result. The increased RDW is supported by evidences that suggest higher RDW result from ineffective erythropoiesis due to chronic inflammation [33]. Inflammatory cytokines have been found to smother the maturation of erythrocytes, which enable juvenile red cells to enter into the circulation and increases the heterogeneity in size [34]. In addition, raised RDW may reflect enhanced erythropoiesis coming about because of the circulating levels of neurohormonal mediators, which lead to an increase in the heterogeneity of circulating red cells [35].

This study also revealed that the median± IQR value of MPV is higher in hypertensive patients (9.55 ± 2.22) compared to control group (9.04 ± 1.06). This result is in line with a study conducted in Gondar, Ethiopia [8]. The possible mechanisms for the increased MPV could relate to vascular injury in hypertensive patients. High blood pressure causes endothelial damage, which leads to increased PLT activation and initiation of PLT production. Evidences suggest that PLT consumption increases at the site of injured blood vessel; which causes larger PLTs to escape from the bone marrow. This leads to increment in PLT count and MPV. Since larger PLTs are hemostatically more active than mature one, their presence becomes a risk factor for development of coronary thrombosis and myocardial infraction [36, 37].

As to the correlation of hematological parameters and blood pressure indices, HCT level was significantly and positively correlated with both systolic (r = 0.219, P = 0.027) and diastolic (r = 0.354, P = 0.00) blood pressures. This finding is in line with studies from Ethiopia [8] and Italy [28]. A study from Nigeria [38] however, found a negative correlation between HCT and blood pressure indices. The exact reason behind positive correlation of HCT with blood pressure is still unknown but it might be related to an increase in red blood cell mass which increases with blood pressure.

RBC count was also weakly and positively correlated with systolic (r = 0.255, P = 0.01) and diastolic (r = 0.241, P = 0.015) blood pressures in our study. This result is in accordance with Enawegaw et al. [8].This association could be explained by the augmentation of growth factors due to distended vascular injury caused by increased blood pressure [6]. RDW was also positively correlated with systolic (r = 0.418, P = 0.000) and diastolic (r = 0.281, P = 0.004) blood pressure. This positive correlation could be related to the amplified chronic inflammation which comes from increased blood pressure [33].

With respect to the correlation of hematological indices with BMI in hypertensive patients, WBC count achieved positive correlation with BMI (r = 0.208). This could be due to the fact that adipose tissue is a great source of inflammatory factors, such as interleukin(IL)-6 and IL-8, which are also important inducers of WBC production [39]. RDW also achieved significant positive correlation with BMI (r = 0.198). This might be due to the fact that, obesity is characterized by chronic, low grade, systemic inflammation which could lead to impaired erythropoiesis there by elevating RDW [40].

In present study, duration of illness since diagnosis of hypertension achieved significant but negative correlation with platelet count (r = -0.219, P = 0.027) and positive correlation with MPV (r = 0.255, P = 0.01). This could be due to the fact that, vascular complication in hypertensives worsens with longer duration. This means, the vascular injury and consequent platelet activation leads to consumption of platelets and escaping of larger PLTs from the bone marrow [41]. This could lead to lower platelet count and high MPV.

Finally, the effect of hypertensive treatment on the hematological parameters were not assessed and using this study as baseline, more advanced studies that include lipid profile of patient and control are required to address these problems and to fully comprehend the role of hematological parameters in the prognosis and management of hypertension related complication.

Conclusion

In the present study, the median values of WBC count, Hgb, HCT t, RDW and MPV was significantly higher in hypertensive patient compared with healthy controls. In the bivariate spearman correlation analysis, RBC count, HCT and RDW showed significant correlation with blood pressure indices. Duration of illness also achieved significant correlation with platelet count (r = - 0.219) and MPV (r = 0.255). Thus, investigation of hematological parameters might help in earlier identification and timely intervention of hypertension complication related to abnormal hematological parameters. However, further studies are required to understand hypertensive associated changes in hematological parameters.

Questionnaire for hypertension patients and controls.

(DOCX)

Click here for additional data file.

SPSS data sheet.

(SAV)

Click here for additional data file.

7 Apr 2021

PONE-D-21-02215

A comparative study of hematological parameters between hypertensive and normotensive individuals in Harar, eastern Ethiopia.

PLOS ONE

Dear Dr. Gelan,

Your manuscript has now been reviewed by two referees who have raised concerns over the lack of detail regarding the sampling technique, as well as the definitions for hypertensives and control patients. There is also some ambiguity over the number of males and females in this study. Since this is fairly important information I invite you to submit a revised version of the manuscript that addresses the points raised by the reviewers and includes the needed information.

Please submit your revised manuscript by May 21 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Colin Johnson, Ph.D.

Academic Editor

PLOS ONE

Journal Requirements:

When submitting your revision, we need you to address these additional requirements.

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

and

2. We suggest you thoroughly copyedit your manuscript for language usage, spelling, and grammar. If you do not know anyone who can help you do this, you may wish to consider employing a professional scientific editing service.

Whilst you may use any professional scientific editing service of your choice, PLOS has partnered with both American Journal Experts (AJE) and Editage to provide discounted services to PLOS authors. Both organizations have experience helping authors meet PLOS guidelines and can provide language editing, translation, manuscript formatting, and figure formatting to ensure your manuscript meets our submission guidelines. To take advantage of our partnership with AJE, visit the AJE website (http://learn.aje.com/plos/) for a 15% discount off AJE services. To take advantage of our partnership with Editage, visit the Editage website (www.editage.com) and enter referral code PLOSEDIT for a 15% discount off Editage services.  If the PLOS editorial team finds any language issues in text that either AJE or Editage has edited, the service provider will re-edit the text for free.

Upon resubmission, please provide the following:

The name of the colleague or the details of the professional service that edited your manuscript

A copy of your manuscript showing your changes by either highlighting them or using track changes (uploaded as a *supporting information* file)

A clean copy of the edited manuscript (uploaded as the new *manuscript* file)

3. We noticed you have some minor occurrence of overlapping text with the following previous publication(s), which needs to be addressed:

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.960.2896&rep=rep1&type=pdf

https://link.springer.com/article/10.1186/s12878-017-0093-9

https://www.wjgnet.com/2220-3168/full/v5/i2/93.htm

In your revision ensure you cite all your sources (including your own works), and quote or rephrase any duplicated text outside the methods section.

Further consideration is dependent on these concerns being addressed.

4. Please provide a sample size and power calculation in the Methods, or discuss the reasons for not performing one before study initiation.

5. Please include additional information regarding the survey or questionnaire used in the study and ensure that you have provided sufficient details that others could replicate the analyses. For instance, if you developed a questionnaire as part of this study and it is not under a copyright more restrictive than CC-BY, please include a copy, in both the original language and English, as Supporting Information.

6. 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.

In your revised cover letter, please address the following prompts:

a) 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.

b) If there are no restrictions, please upload the minimal anonymized data set necessary to replicate your study findings as either Supporting Information files or to a stable, public repository and provide us with the relevant URLs, DOIs, or accession numbers. Please see http://www.bmj.com/content/340/bmj.c181.long for guidelines on how to de-identify and prepare clinical data for publication. For a list of acceptable repositories, please see http://journals.plos.org/plosone/s/data-availability#loc-recommended-repositories.

We will update your Data Availability statement on your behalf to reflect the information you provide.

7. Your ethics statement should only appear in the Methods section of your manuscript. If your ethics statement is written in any section besides the Methods, please delete it from any other section.

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Partly

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: I Don't Know

**********

3. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: No

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: 1. Authors did not show how they calculated the sample size. They should explain how they got the sample size.

2. Authors did not state the number of males and female in both cases and controls. This should be stated in the manuscript.

3. The sampling techniques was not well described in the methodology. The mention of convenient sampling is not enough.

4. The criteria for selecting the controls is not clearly described in the methodology section. Authors must describe this.

5. The operational definitions for the cases (hypertensives) and controls (normotensive) are not stated clearly stated. Authors must describe this.

Reviewer #2: I have read your manuscript with interest. In general, the paper addresses an issue that admittedly needs more study and attention. This is a manuscript where the authors examined the "A comparative study of hematological parameters between hypertensive and normotensive individuals in Harar, eastern Ethiopia".

1. While appreciating the challenge of preparing a manuscript in the English language for many authors, the paper should be carefully edited by a native English-speaking editor.

2. No information about the physical activity records.

3. Please explain more about the implication of this study results. How can the study results help clinically?

4. The Discussion would be improved by detailing more specific implications for future studies.

5. The limitation of the study should be fully explained in the discussion section.

6. Please describe more about the novelty of manuscript in the introduction. It is very important for readers to know about this novelty.

**********

6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

29 Jun 2021

Cover letter

Moges Wordofa

Addis Ababa University

Addis Ababa, Ethiopia

Email: heranmakmow@gamil.com or moges.wordofa@aau.edu.et

Date: May 21, 2021

To: PLOS ONE

Dear Editorial:

We are glad to write this response to our paper entitled as “A comparative study of hematological parameters between hypertensive and normotensive individuals in Harar, eastern Ethiopia” (Manuscript ID: PONE-D-21-02215) which has been requested to review for publication in PLOS ONE journal. We are pleased to have an opportunity to make our paper revised and we have greatly appreciated the editor’s comments and suggestions which were considered as very helpful. In revising the paper, we have carefully considered your comments and suggestions on our revised submission.

Response to editorial correction

We have gone through the manuscript to edit and amend some editorial correction. By doing so, we have corrected language error and other topographical errors in the document. We have also prepared the manuscript according to PLOS ONE style requirements. Besides, if there is any error that we missed, we are very ready to correct it again.

Response to the reviewer’s comment

Dear Reviewers:

We are glad to write this response to our paper entitled as “A comparative study of hematological parameters between hypertensive and normotensive individuals in Harar, eastern Ethiopia” (Manuscript ID: PONE-D-21-02215) which has been requested to review for publication in PLOS ONE journal. We are pleased to have an opportunity to make our paper revised and we have greatly appreciated your comments and suggestions which were considered as very helpful. In revising the paper, we have carefully considered the comments and suggestions on our revised submission. As instructed, we have attempted to thoroughly explain changes made to all comments and reply to each comment in point-by-point fashion as follows:

Response to Reviewer#1

Comment#1. “Authors did not show how they calculated the sample size. They should explain how they got the sample size.”

Response#1: The sample size was determined from a study in Indian based on mean and variance of hemoglobin. We used 95% CI and power of 0.8 as well as based on formula for double population of equal size mean. However, we enrolled additional participants other than the one we obtained using the formula. The purpose was to increase presentiveness of the sample to the general population.

Comment #2. “Authors did not state the number of males and female in both cases and controls. This should be stated in the manuscript.”

Response #2: The total number of males and females in both normotensive and hypertensive group were equal and it was 39 and 63, respectively. we have already included this in the result section of the manuscript in a previous submission.

Comment #3. “The sampling techniques was not well described in the methodology. The mention of convenient sampling is not enough.”

Response #3. As suggested by the reviewer, we have elaborated the technique in the methodology section.

Comment#4. “The criteria for selecting the controls are not clearly described in the methodology section. Authors must describe this”

Response#4. As suggested by the reviewer, we have clarified the donor selection criteria in methodology part of the manuscript.

Comment#5. “The operational definitions for the cases (hypertensives) and controls (normotensive) are not stated clearly stated. Authors must describe this”

Response#5. As suggested by the reviewer, we have included the definition of normotensive and hypertensive under operational definition in methodology section

Response to Reviewer#2

Comment#1: “While appreciating the challenge of preparing a manuscript in the English language for many authors, the paper should be carefully edited by a native English-speaking editor”

Response#1: The manuscript is thoroughly revised by native English writer in the field and linguistic errors are corrected

Comments#2: “No information about the physical activity records”.

Response#2: we thought it is irrelevant to the study

Comment#3: “Please explain more about the implication of this study results. How can the study results help clinically?”

Response#3: As suggested by the reviewer, the significance of the study is addressed in the introduction part of the manuscript.

Comment#4: “The Discussion would be improved by detailing more specific implications for future studies”

Response#4: It has been included as it could be used as a baseline for performing further advanced studies including lipid profile and others

Comment#5: “The limitation of the study should be fully explained in the discussion section”

Response#5: We have included the limitation of the study in the discussion

Comment#6: “Please describe more about the novelty of manuscript in the introduction. It is very important for readers to know about this novelty.”

Response#6: We have tried to include novelty and necessity of this study among hypertensive patients in the country and worldwide.

Looking forward to hearing from you. Thank you again for your consideration!

Sincerely,

Moges Wordofa

Submitted filename: Response to the reviewers.doc

Click here for additional data file.

27 Jul 2021

PONE-D-21-02215R1

A comparative study of hematological parameters between hypertensive and normotensive individuals in Harar, eastern Ethiopia .

PLOS ONE

Dear Dr. Gelan,

Your revised manuscript has been reviewed, and neither reviewer recommended publication of the revision. Specifically concern has been raised regarding separation of males and females during analysis.  If you believe you can address this issue, submit a revised version of the manuscript that addresses the point raised.

Please submit your revised manuscript by Sep 10 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

Please include the following items when submitting your revised manuscript:

A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'.

A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'.

An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Colin Johnson, Ph.D.

Academic Editor

PLOS ONE

[Note: HTML markup is below. Please do not edit.]

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: (No Response)

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: (No Response)

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: (No Response)

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: (No Response)

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: my comments is that when dealing with hematological parameters, authors will have to seperate male from females in the analysis. hematological parameters for males and female cannot be analysed together they must be separated.

Reviewer #2: (No Response)

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step.

14 Oct 2021

I have tried to address the comment suggested by the reviewer and I have included the correction in the revised manuscript

Thank you

Submitted filename: Response to the reviewers.doc

Click here for additional data file.

17 Nov 2021

A comparative study of hematological parameters between hypertensive and normotensive individuals in Harar, eastern Ethiopia .

PONE-D-21-02215R2

Dear Dr. Gelan,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org.

Kind regards,

Colin Johnson, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

22 Nov 2021

PONE-D-21-02215R2

A comparative study of hematological parameters between hypertensive and normotensive individuals in Harar, eastern Ethiopia.

Dear Dr. Wordofa:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Colin Johnson

Academic Editor

PLOS ONE