Application of Binomial Models on the Determinants of Hypertension Patients in Haramaya Woreda, Eastern Hararghe, Ethiopia

Introduction: Hypertension is along with a medical condition, in which the blood pressure in the arteries is high, which is a major health problem in the community. The main aim of the study was to assess the determinants associated with patients who experienced hypertension in Haramaya Woreda using a binomial model. Methods: A cross-sectional study design was conducted to assess the associated factors of hypertension patients’ complications in the Haramaya Hospital, Eastern Hararghe zone from December 1 st to 30th, 2020. Data were statistically analyzed using the statistical package for social sciences (SPSS) version-23 (SPSS Inc., USA). A sample of 1417 respondents having hypertension chronic disease was included. Statistical tools such as descriptive statistics, chi-square test of association, and binomial regression were used to summarize and interpret the hypertension patients’ dataset and a 5% level of signicance was also used as a baseline comparison. Results: Both chi-square test of association and binomial model revealed that age group, gender, residence, presence of diabetes mellitus and congestive heart failure were signicantly associated with hypertension patients at a 5% level of signicance. Multivariable binomial regression model indicated that an estimated odd ratio(OR) with 95% condence interval were age group of 21-30year3.502(95%CI=1.310-9.361),31-40year6.108(95%CI=2.364-15.782),41-50year 11.070(95%CI=4.276-28.661), 51-60 year 12.530(95% CI=4.890-32.107) and greater than 60 years 12.713(95%CI=4.827-33.482), being male (OR=1.859; 95%CI=1.320-2.617), living in rural (OR=0.545. 95%CI=0.381-0.778).The presence of diabetes mellitus (OR=0.028, 95%CI=0.019-0.040), and congestive heart failure (OR=0.017, 95%CI=0.009-0.032) are associated risk factors of hypertension patients. Conclusions: The main hypertension risk factors were age category, gender, residence, having diabetes mellitus, and congestive heart failure (p=0.0001). Those were signicantly associated with hypertension in both the chi-square test of association and binomial model. To predict the participants being a hypertensive binomial model with logit link function best t the dataset.


Introduction
Hypertension is a long-term medical condition in which the blood pressure in the arteries is high.
Hypertension is a chronic health disorder characterized by higher blood pressure (BP) in the blood vessel and determined as raised systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg in adults aged 18 years and above{Animut, 2018 #4;Asresahegn, 2017 #2;Legese, 2020 #5} [1]- [4]. Longterm high blood pressure is a major risk factor for coronary artery disease, stroke, heart failure, atrial brillation, peripheral arterial disease, vision loss, chronic kidney disease, and dementia. Blood pressure is expressed by two measurements such as systolic and diastolic pressures, which are the maximum and minimum pressures, respectively. High blood pressure is divided into primary hypertension or secondary hypertension. About 90 up to 95% of cases are primary, de ned as high blood pressure due to nonspeci c lifestyle and genetic factors. On average, systolic and diastolic blood pressures were 125.3 mmHg and 78.5 mmHg, correspondingly [5].The average systolic and diastolic blood pressure respectively were 117.0 mmHg and 75.5 mmHg [6].
Hypertension is the top leading cause of the global burden of disease [7]. Because of its associated risks of cardiovascular and kidney diseases such as myocardial infarctions, strokes, and renal failures as well as its frequent disease, hypertension disease is the main health challenge in the community [1].
Hypertension affects around 22% of people aged 18 years and above and it is responsible for an estimated 9.4 million deaths per year globally [8], [9]. ]. Hypertension is a worldwide public health problem and it is a risk factor for cardiovascular disease. An estimated 1.13 billion people worldwide have hypertension, most (two-thirds) living in low-and middle-income countries [10].
According to World Health Organization, African Region has the highest prevalence of hypertension (27%) while the American Region has the lowest prevalence of hypertension (18%) [10].The increasing prevalence of hypertension in developing countries is a major concern. According to recent estimates from the World Health Organization, two-thirds of hypertensive people live in developing countries including Ethiopia [11]. Hypertension is the leading risk factor for cardiovascular disease and death in Africa. It is a public health problem and big economic impact in Africa. This is because a signi cant proportion of the productive population is affected by hypertension and its complications [12]. Almost three-quarters of people with hypertension live in developing countries where people have very low awareness of hypertension [13]. The prevalence of hypertension is increasing in Africa rising from 19.7% in 1990 to 30.8% in 2010 [14].
A review of current trends shows that the number of adults with hypertension increased from 594 million in 1975 to 1.13 billion in 2015, with the increase seen largely in low and middle-income countries. The lower-income countries include Ethiopia have been affected by double burden diseases. The WHO 2011 report showed that 34% of all deaths in Ethiopia were due to non-communicable diseases, from which cardiovascular disease contributes 15% [15].Burial surveillance in Addis Ababa also revealed that 51% of all deaths were due to non-communicable diseases, of which cardiovascular disease was a main cause of death (24%), and hypertension was responsible for 12% of the cardiovascular disease deaths [16].
Some studies have been done on hypertension that swept the worldwide. According to the World Health Organization's recent update [9], hypertension is one of the top ve continuing risk factors for cardiovascular deaths in the world. The World Health Organization (WHO) predicted deaths from noncommunicable diseases (NCDs) would increase globally by 17% over the next ten years where the greatest increase will be in the African region (by 27% or 28 million deaths from NCDs) [17]. Raised blood pressure is the principal risk factor for worldwide mortality in which 9.4 million deaths and 7% of disease burden in 2010 were caused by elevated blood pressure. If blood pressure is left uncontrolled, hypertension causes stroke, myocardial infarction, cardiac failure, dementia, renal failure, and blindness [1]. Concerning the deviations in regional and residence adults with hypertensive were 40% in the world and 46% in Africa [18]- [20]. Regarding the problem with hypertension disease, the peoples are not responsive to their health status to the timely and suitable intervention, the symptoms of the disease do not appear until complications of a heart attack happen, developed severe disabilities like heart failure, chest pain, and irregular heartbeat which leads to sudden death in many guys with elevated blood pressure [4].
According to World Health Organization, the method that discourses treatment decisions relied on individual risk factors is less cost-effective than the technique that addresses total cardiovascular risk [21], [22].World Health Organization recommends a total risk tactic that enables assimilated control of hypertension, diabetes, and other cardiovascular risk factors in primary care and targets available resources at persons most likely to develop heart attacks, strokes, and diabetes complications [15], [23] Diabetes contributes a huge burden of disease so that diabetic patients exhibit a very high prevalence of hypertension. People have a high prevalence of hypertension that is three times more affected than the general population [24].According to the study done in sub-Saharan Africa, as a result of diabetes, the total disability-adjusted life years were increased by 126•4% between 1990 and 2017, thus, the decide largest change observed across all level 3 causes of NCD burden. Diabetes in sub-Saharan Africa has not only increased in terms of total disability-adjusted life years, but also in terms of crude and agestandardized disability-adjusted life year rates, as well as years of life lost and years of life lived with disability rates [25]. Diabetes status was a signi cant risk factor as evidenced by the prevalence of hypertension among 29.9%, 44.0%, and 53.3% for normoglycemic, prediabetes, and diabetic individuals, respectively [26]. The residence status of the patient was found to have a signi cant factor of hypertension among its prevalence that 33.5% for Atbara, 39.5% for Ed Damer, 30.4% for Shendi, and 41.0% for berber [26]. The study conducted by Huang et al., (2020) reported that compared with nonhypertensive patients, hypertensive patients were older (58-73 vs 40-68), had higher rates of diabetes (28.3% vs 8.1%), and had a higher mortality rate (24.8% vs 15.2%). Different studies in Ethiopia and others revealed that increased risk of hypertension was associated with older age (> = 45 years), obesity[28], smoking [29] and chat chewing [29], [30].
In spite of the fact that several studies have been done on hypertension using a summary measure of statistics, meta-analysis to predict the effect of associated factors by ignoring the covariates are at the level of the study rather than the level of the subject, and the dependent variable is the effect size in the studies rather than subject scores. An up-to-date and comprehensive assessment of the evidence concerning hypertension in Ethiopia is lacking. Thus, this study assessed associated factors of Hypertension patients and the application of Binomial models in Haramaya Woreda, Eastern Hararghe, and Ethiopia.

Study Design, and Period
A cross-sectional study design was conducted to investigate the factors associated with hypertension patients' complications in Haramaya Hospital, Eastern Hararge Zone, Ethiopia. Haramaya hospital is one of the public hospitals in the East Hararge zone which is found in Ethiopia and was established in 2000.
The admitted hypertension patients and related health complaints were deliberated as hospital admission due to high hypertension complications. All patients admitted to the medical ward of the hospital from January 1st, 2019 to December 30th, 2020 due to hypertension-related health conditions such as stroke, cardiovascular, renal, or peripheral vascular diseases, and hypertensive emergencies were included in this study. However, patients with those health conditions and additional comorbidities such as diabetes mellitus, and patients with <140/90mmHg blood pressure at admission or with no documented antihypertensive medication history were excluded from this study.

Data Sources and Collection Procedures
Hypertension was de ned as admission blood pressure of ≥140 mmHg systolic and/or ≥90 mmHg diastolic or previously on anti-hypertension medication. Blood pressure was measured by the physician or nurse at the emergency department using a standard mercury sphygmomanometer. Patients were allowed to sit for 5 minutes before measurement then at least two blood pressure measurements; spaced 1-2 minutes apart were taken. This was repeated every 30 minutes until the patient gets stable per the national guideline [31]. We took the average of the rst two consecutive records as the patient's blood pressure at admission. We considered the type of hypertension complication recorded on the patient discharge notes as the nal diagnosis of hypertension complication.
Data were collected through reviewing medical records; admission logbooks and patient folders by the investigation team using a data extraction sheet. First, we reviewed medical admission logbooks to count the sex and admission outs of all medically admitted patients and to identify and prepare the list of Unique Medical Record Number (UMRN) of 1417 patients admitted due to hypertension complications. Then, using patients' UMRN those patient folders were drawn from the medical record room and reviewed for data collection. Data retrieved from patient and tuberculosis screening results.

Variables of the study
Dependent Variables of the study: The dependent variable is hypertension complication that coded as 1 for the presence of hypertension complication and 0 for the absence of hypertension complication.
Independent variables of the study: The independent variables were age group sex, residence, diabetes mellitus, congestive heart failure, and tuberculosis screening results.

Operational De nition of the terms
Hypertension is a higher blood pressure that determined as raised systolic blood pressure ≥140 mmHg or diastolic blood pressure ≥90 mmHg [1], [3], [4].
Diabetes mellitus is a group of metabolic diseases in which there are high blood sugar levels over a prolonged period This high blood sugar produces the symptoms of frequent urination, increased thirst, and increased hunger [32].
Heart failure is a chronic, progressive condition in which the heart muscle is unable to pump enough blood to meet the body's needs for blood [33] .
Congestive heart failure is a type of heart failure that requires seeking timely medical attention, although sometimes the two terms are used interchangeably.
Tuberculosis screening results is de ned as the identi cation of people with suspected active TB, in a predetermined target group, using tests, examinations or other procedures that can be applied rapidly [34].

Methods of Data Collection and Data Analysis
The collected data were checked for completeness and consistency daily by principal investigators. The data was entered into SPSS version 23 statistical software for analysis.

Speci cation of Binomial regression model
This model describes the relationship between a dichotomous response variable and a set of continuous or discrete explanatory variables [35]. The logistic regression model has become the statistical model of choice [36]. First, it considers the case where the response variable y i is binary, assuming only two values that are coded as one or zero. (1) We view y i as a realization of a random variable Y i (hypertension complication) that can take the values one and zero with probabilities π i and 1 − π i , respectively. The Binomial Regression model is the family of Generalized Linear Models. GLMs are used to model the relationship between the expected value of a response variable y and a linear combination of the explanatory variables vector X using link function such as logit and probit.
Odds ratio of binary logistic regression: The logistic regression function can be expressed in terms of odds ratio.
This expression de nes a multiplicative model for the odds. For instance, if we were to change the j th predictor by one unit while holding all other variables constant, we would multiply the odds by . Following some algebraic manipulation, the following intrinsically linear function is produced.   21.5%(305) for 51-60, and 14.0%(199) for more than 60 a long time though the remaining 8.9% have less than twenty years old. Patients who experienced diabetes mellitus within the clinic were around 55.5% of the entire a rmation and 44.5% did not have diabetes.
Inlined with this tall rate of diabetes patients the chi-square test of a liation appeared that there's a measurable a liation between those persistent maladies of hypertension and diabetes (p-value=0.00001). Most of the patients with hypertension were not experienced congestive heart disappointment 81.5%( 1155) and had negative Tuberculosis screening comes about 94.3%( 1336). Be that as it may, around 18.5% (262) of the patients had congestive heart disappointment unremitting illnesses which have a solid a liation with hypertension.
The comes about of the chi-square test of a liation shown in Table 1 uncovered that Age group, sex, Home, nearness of diabetes mellitus, and congestive heart disappointment were altogether related to the hypertension patients at a ve percent level of noteworthiness. This suggests the nearness of those components deciding the presentation hazard of the encompassing community for the unremitting hypertension illness in Haramaya Woreda. In expansion, the age dispersion of respondents appeared that more of the patients were in Age category of 41-50 and 51-60 a long time as shown in Figure1. But Tuberculosis has no such impact on the hypertension patients of the clinic conceded within the current study. Most of the hypertensive patients were found in Age bunch of 51-60 a long time while youthful age bunches of less than 20 a long time were less uncovered to be hypertensive as demonstrated in Figure 1.

Classi cation of Hypertension patients' data
A classi cation Table 2 was used to summarize the predictive power of a binary logistic model. In this case, the Table cross-classi es the binary response with a prediction of whether respondents were not experienced hypertension (y = 0) or had experienced hypertension (y = 1). Therefore, the predictive power of the binary logistic regression model for hypertension patients being correct classi cation was 88.0% based on the cutoff value of 0.5. Table 2 Classi cation of hypertension patients.
Observed Predicted

Hypertension Percentage Correct
No Yes Step

Link function for Model Comparison and Model Summary
Model selection was done using Akaike information criteria and comparisons have been made between the link function of logit, probit, and identity. Based on the result of the generalized linear model with the respective link function, binary logistic with logit link function has the smallest Akaike information criteria(AIC=267.102) and Bayesian information criteria (BIC=324.932) among the candidate model which implies that model with logit link function best t of the hypertension dataset. In addition, loglikelihood and deviance statistics are also inlined with the logit link function of binary logistic regression as observed in Table 3. As a result, the risk of being hypertensive was more than three-fold for 21-30 years, six-fold for 31-40 years, eleven-fold for 41-50 years, and more than 12 fold for greater than 50 years higher as compared to their counterparts.
Another important factor was the Residence of respondents which is potentially affecting the hypertension patients in the surrounding. An estimated odds of living in rural area was 45.5% times less likely to develop hemoglobin complications' than being resident in urban (OR=0.545. 95%CI=0.381-0.778). In addition, respondents having diabetes mellitus (OR=0.028, 95%CI=0.019-0.040) and congestive heart failure (OR=0.017, 95%CI=0.009-0.032) were less developed hypertension chronic disease than those who haven't Diabetes and heart failure Respectively as indicated in Table 4. The goodness model has been checked using the Hosmer and Lemeshow test which suggested that the binomial model of logit link function was an appropriate model to predict and analyze the hypertensive patients' data set (chi-sq=11.00, P-value=0.202). Table 4 Results of nal binomial model with logit link function parameter estimation. candidates' models. Hosmer and Lemeshow test also indicated that the binomial model with logit link function was a good t for the hypertensive dataset. The prevalence for hypertension patients was 26.3%.
Both chi-square test of association and binomial model showed age group of patients\ had a signi cant effect on being hypertensive. The risk of respondents experiencing hypertension was increased as the Age of patients increased. As a result, the risk of being hypertensive was more than three-fold for 21-30 years, six-fold for 31-40 years, eleven-fold for 41-50 years and more than 12 fold for greater than 50 years higher as compared to younger age. This study consistent with study done by [39]- [41]. As the age increased for the patients the incidence risk of disease also increased which is in-lined with [13], [42], [43]. Another important factor associated with hypertensive was Gender of respondents which had signi cant effect on hypertension patients at 5% level of signi cance. The parameter estimation of binomial model indicated that the odds of female gender associated to being hypertensive was increased 1.859 times more as compared to counterpart. This implies females were more vulnerable part of society with hypertension disease in Haramaya Woreda and there was positive association between gender and being hypertensive. This study con rmed with study done in Nepal [13], [44]. Also study done in Debre Markos Town supported that being female was associated with hypertensive [20]. Other important factors were presence of chronic disease diabetes mellitus and congestive heart failure which is signi cantly associated with being hypertensive. The odd of having diabetes mellitus was 2.8% less likely to develop hypertension than non-diabetes patients in the Haramaya woreda residents. This implies being admitted for diabetes mellitus treatment at hospital deceased the risk of developing chronic disease hypertension or non-diabetes people had more probability of exposed to hypertension disease in the community. The reason may be the health complication of diabetes was treated in the way that it decreases the risk of hypertensive person. Congestive heart failure also has signi cant effect on the respondents being hypertensive.

Conclusions
The prevalence of chronic hypertension was 26.3% among the study participants. Age category of respondents, gender, residence, having diabetes mellitus and congestive heart failure were independent predictors of hypertension. To predict and estimate the parameters of participants being hypertensive binomial model with logit link function was an appropriate model as the result of Hosmer and lemeshow statistic indicated (χ 2 = 11.00, p-value=0.202). The healthcare providers are recommended to give due attention for older age, women, urban resident and serious care for participants having diabetes mellitus and congestive heart failure in order to minimize the occurrence of hypertensive. On the top of this, future planning should be turn face to trainee the health services professional.

Declarations
Ethics approval and consent to participate Letter of ethical clearance was obtained from Haramaya University, Department of Statistics and submitted to Haramaya Hospital to get permission to conduct this research. This study was developed in accordance with established legislation and complies with the norms of good clinical practice, and informed consent was being not necessary as personal identifying information was kept separate from this research data. Finally, the study protocol was approved by the ethics committee or medical directors of the Hospital.

Consent for publication
Not Applicable Availability of data and materials The raw data used in this study can be accessed from Haramaya Hospital.

Competing interests
The authors declare that they have no competing interests.

Funding
This Research has no fund.
Authors' contributions KK,MM and MW was involved in the conception and design of the study, drafting the manuscript, review of protocol development, interpretation of the data and review of the manuscript. All authors read and approved the nal manuscript. GraphicalAbstractimage.docx