Assessment of Blood Pressure Control among Hypertensive Patients in Southwest Ethiopia

Background The rate of blood pressure control among hypertensive patients is poor and the reasons for poor control of blood pressure remain poorly understood globally. Objective To assess the rate of blood pressure control among adult hypertensive patients at Jimma University Specialized Hospital. Materials and Methods We conducted a hospital based cross sectional study among adult hypertensive patients at Jimma University Specialized Hospital hypertension clinic from March 4, 2015 to April 3, 2015. Data on sociodemographic characteristics of the participants and adherence to antihypertensive medication(s) were collected from patients by face to face interview using a pretested structured questionnaire. Comorbidities, antihypertensive medication(s) and blood pressure measurements were collected retrospectively from medical records. Medication adherence was assessed using Morisky’s Medication Adherence Scale-8 score. We did the statistical analysis using chi-square test and binary logistic regression with level of α set at 0.05. Statistical significance was considered for variables with p<0.05. Results Out of 311 participants, 286 patients were eligible and were studied. More than half, 154 (53.8%), of the participants were males. The mean age of the participants was 54.8± 12.6 years (range 26 to 94). The majority, 196 (68.53%), of the participants were taking more than one antihypertensive medication. More than one third (39.5%) of the participants were non adherent to their medication(s). The rate of blood pressure control was 50.3%. In a univariate logistic regression analyses, age ≥65 years old (P = 0.008), physical inactivity (p<0.001), chat chewing (P<0.001), adding salt to food (P<0.001), and coffee use (P<0.001) are significantly associated with uncontrolled blood pressure Conclusion Almost half of the hypertensive patients on follow up had uncontrolled blood pressure. We recommend better health education and care of patients to improve the rate of blood pressure control at the hospital.


Introduction
There are a limited number of researches on BP control status of hypertensive in Ethiopia. The lack of adequate studies on hypertension significantly affects hypertension management and care of hypertensive patients in the country. Thus, this study aimed to assess BP control status among adult hypertensive patients at Jimma University Specialized Hospital (JUSH).

Materials and Methods
We conducted a hospital based cross sectional study among adult hypertensive patients at Jimma University Specialized Hospital (JUSH) hypertension clinic from March 4, 2015 to April 3, 2015. Jimma University Specialized Hospital (JUSH) is both a referral and teaching hospital with 523 beds serving for, approximately, 20,000 admissions and 140, 000 outpatient visits a year. It serves for a catchment population of about 15 million people. Hypertensive patients get follow up care and antihypertensive medications at hypertension clinic every month. The clinic provides service for 1694 ambulatory hypertensive patients.
The study was approved by Jimma University Collage of Public Health and Medical Sciences Ethical Review Committee. Prior to data collection on sociodemographic characteristics and adherence of participants to antihypertensive medication(s), each participant signed a written informed consent. We conducted a face to face interview with a pretested structured questionnaire. The participants had a right to withdraw from participation. Comorbidities, antihypertensive medication(s) and blood pressure measurements were collected from medical records of patients using a pretested data abstraction format.
To maintain the validity of the data collection tool, a structured questionnaire was developed and translated to local languages (Amharic and Afan Oromo) and back translated to English. We used Morisky's Medication Adherence Scale (MMAS-8) to assess the participants' medication adherence.
Physical activity was assessed by asking each participant the number of minutes per day and the number of days per week a patient spent doing physical activity. The participants were classified into physically active if they reported that they were farmer or if they reported that they exercise greater than 30 minutes for greater than 5 days of the week otherwise they were classified as physically inactive. Body weight was measured to the nearest 0.1kg using a digital scale and height was measured to the nearest 0.1cm in the standing position using a portable height board. Body mass index was calculated as weight in kilogram divided by squared height (meter square).
Participants included in the study were all hypertensive patients getting follow up at JUSH hypertension clinic. Participants !18 years old who were on follow up for at least 12 months and whose medical records contained complete pertinent data and who were willing to participate were included. Seriously ill patients not able to complete the interview and patients with incomplete medical records such as demographics and BP were excluded. The data were collected by six clinical nurses working at Jimma University Specialized Hospital (JUSH).
Data extracted included sociodemographic characteristics, co-morbidities, adherence status of patients to antihypertensive medication(s), type of antihypertensive medication(s), duration of hypertension, and one year blood pressure measurements. The main outcome of the study was blood pressure control status.

Statistical Analysis
We analyzed the data using SPSS Version 20.0 (Chicago, SPSS Inc.). We conducted a univariate logistic regression analyses to identify factors that are associated with uncontrolled blood pressure. Variables with P<0.05 were considered statistically significant.

Operational definitions
Hypertension was defined as a sustained high blood pressure (SBP!140 or DBP !90mmHg) or reported regular use of anti-hypertensive medication(s) [9]. Uncontrolled blood pressure was defined as systolic blood pressure of !140 mmHg and/or diastolic blood pressure of !90 mmHg [27]. Controlled blood pressure was defined as systolic blood pressure of <140 mmHg and/or diastolic blood pressure of <90 mmHg [28]. Patients were considered as adherent to their medication(s) when Morisky's medication adherence scale (MMAS-8) score was less than 3 [29,30] and non-adherence was considered when the patient's MMAS-8 score was !3. Overweight was considered if BMI was between 25 and 29.9 kg/ m2 [31]. Obesity was defined as BMI !30kg/m2 or waist circumference >102 cm for men and > 88 cm for women [31].

Baseline characteristics of the participants
In this study, a total of 311 participants were interviewed and 286 of them were eligible and studied. The response rate was 92%. As shown in table 1, one hundred fifty four (53.8%) of the participants were males. The mean age of the participants was 54.8 ± 12.6 years (range from 26-94 years). Two hundred twenty six (79.0%) of the participants were married. The most common religions were Islam, 145 (47.2%) and Orthodox Christianity, 125 (43.7%).
The majority, 160 (55.9%), of the participants have been taking salt with food. More than half, 158 (55.2%) of the participants were physically inactive. Nine participants (3.11%) were cigarette smokers, 48 (16.8%) were alcohol drinkers and 122 (42.7%) were chat chewers. The majority, 167 (58.4%), of the participants have been drinking coffee ( Table 2). The majority, 173 (60.5%), of the participants were overweight. The mean duration of hypertension was 5 ± 4.1 years. More than half, 103 (51%), of the participants had hypertension for less than five years.

Antihypertensive medications
Out of the 286 participants, 196 (68.53%) were prescribed with more than one antihypertensive medication. The majority, (52.1%), were on two medications and 84 (29.4%) were on mono-therapy. Seventy seven (27%) of the participants on two medications had uncontrolled BP. Fifty three (18.6%) of the participants on monotherapy had controlled blood pressure. Forty six (16.1%) participants were prescribed with triple antihypertensive medications and only one participant was on four antihypertensive medications. The number of antihypertensive medications prescribed was not associated with blood pressure control status (P = 0.094). Ninety two (32.2%) of the participants have been getting their medication for free. Dietary approach to stop hypertension (DASH) therapy was practiced by 6 (2.4%) of the participants.
According to MMAS-8 score, 173(60.5%) of the participants were adherent to their antihypertensive medications ( Table 4). The MMAS-8 score of the participants ranged from 0-7. No participant had MMAS-8 score of 8. Seventy four (25.9%) of the participants had a MMAS-8 score of 2 and 64 (22.3%) had a MMAS-8 score of 1. Forgetting medication(s) was the most common reason for non-adherence.

Blood pressure control and associated factors
The rate of blood pressure control in this study was 50.3%. The mean SBP was 132.13 ± 20.30 mmHg and mean DBP was 81.5±12.1 mmHg. We performed univariate analyses to identify factors associated with uncontrolled hypertension (Table 5). Age !65 years old (P = 0.008), physical inactivity (p<0.001), chat chewing (P<0.001), adding salt to food (P<0.001), and coffee use (P<0.001) are significantly associated with uncontrolled BP.

Discussion
In this study about half, (49.7%), of the participants had uncontrolled blood pressure. More than half, 60.5%, of the participants were adherent to their antihypertensive medications. Diabetes mellitus and peripheral neuropathy were the commonly encountered co-morbidities among hypertensive patients. In our study more than half, 60.5%, of the study subjects were adherent to their antihypertensive medication(s). In United Arab Emirates [32], adherence to antihypertensive medication(s) was reported to be 54.4% which is lower than our finding. This may be attributed to the presence of comorbidities and advanced age of the patients which may significantly affect medication adherence. In Nigeria [33], the level of medication adherence was reported to be 33.3%. This is lower than our finding. This is because a significant number (31.4%) of the participants had depression which in turn may affect medication adherence. In our study, we excluded patients with depression and other psychiatric disorders. The level of adherence in our study is also higher than the finding in Congo (45.8%) [34]. This noted difference in adherence between ours and Congo may be explained by the difference in socio-demographic characteristics. The study participants in Congo were older than ours (mean age 63.3±9.6years vs. 54.8±12.6 years). In addition, in Congo, 53.9% participants had comorbidities; 55.9% had medication related side effects and 67.6% had stress/anxiety all of which may affect medication adherence. The level of medication adherence in our finding is lower than the Egyptians [35] which may be attributed to a difference in quality of care provided and socioeconomic differences. For example, Ethiopia is a low income country with a percapita income of $550 US dollar. The difference in the study design might also have contributed for lower level of adherence in our study. We used MMAS-8 to measure adherence and adherence was considered if the MMAS-8 is <3 while the Egyptians considered adherence if the patient took >90% of the doses in a month. Our finding is also comparable to the finding in Sudan [36] where 59.6% of patients were compliant to their medication(s) as measured with the pill count method.
The level of adherence in our finding is similar to the findings in Gondar, Northwest Ethiopia (64.6%) and Adama, Southeast Ethiopia (59.5%) [28,37]. This might be due to similarity of socioeconomic characteristics of the participants. We found that 27.2% of the participants had diabetes mellitus co-morbidity. This finding is in line with the finding from Brazil (29.8%), but lower than the finding from Bahrain (55.8%) [38]. This may be due to high prevalence of obesity (43.6%) in the participants enrolled in Bahrain study [38]. The low prevalence of other comorbidities in this study could be due to low availability of diagnostic materials and laboratory facilities. The level of comorbidity in our finding is also lower than the findings in Congo (53.9%) [34] which may be related to older age of participants in Congo, the difference in early identification and diagnosis of comorbidities or the difference in life style factors between ours and the Congo population.
The rate of BP control in our study was 50.3%. This is lower than the findings reported from Bahrain (66.3%) and USA (69.7%) [17,38]. The higher level of adherence in Bahrain and USA may be due to better medical and pharmaceutical care to patients, better percapita income, and better education and awareness of patients to hypertension and treatment in these countries. However, in our setup, more than 80% of the population is rural resident and the annual income is very low that may affect medication adherence.   [12,34,39]. This might be due to high prevalence of physical inactivity, bad dietary habits, obesity, the presence of comorbidities, and elderly population. For example, in South Africa, 80% of the study participants had other comorbid diseases and 66% had psychological stress. In Congo, the study participants were older than ours; 53.9% had comorbidities and 67.6% had stress or anxiety.
In Kenya, 64.7% of the renal transplant recipients attending nephrology clinics had uncontrolled hypertension (BP!130/80 mmHg) [40] which is much higher than our finding. The difference in the study population might have contributed for this difference as the Kenyans studied renal transplant recipients only. Our finding is comparable to the finding from Egypt [35] where 53.2% participants had controlled BP while the level of adherence is higher than ours. The reason for this similarity may be because of high prevalence of comorbidities in 34.5% of the participants otherwise there is no justifiable reason for this similarity.
The rate of BP control was relatively similar to the study in Addis Ababa, Ethiopia (40.1%) and Gondar, Ethiopia (46.6%) [37,41]. This could be due to socioeconomic similarity of the participants and almost similar level of care provided to patients.
Literatures showed that age is strongly related to systolic blood pressure and isolated systolic hypertension accounts for the majority of cases with uncontrolled BP in individuals greater than 60 years of age [42]. However, according to the joint national committee eighth meeting (JNC8) guideline, the systolic threshold for controlled hypertension is 150 mm Hg which is higher than the threshold for uncontrolled blood pressure (140 mm Hg) [2]. This could contribute to the high prevalence of uncontrolled hypertension in older age groups.
For many hypertensive patients, combination therapy is believed to achieve better BP control than monotherapy [43]. In our study, 12.6% of the participants were on monotherapy despite uncontrolled blood pressure. This is in line with the study from Zimbabwe [12]. This may be attributed to shortage of senior physicians and clinical pharmacists providing better care for ambulatory hypertensive patients to optimize appropriate combination therapy based on BP control status. The availability and cost of antihypertensive medication(s) may also be a challenge forcing the prescribers to continue with monotherapy even when it is inadequate.

Conclusions
Our study revealed that almost half of the participants had uncontrolled BP. More than half of the participants were adherent to their antihypertensive medications. Diabetes mellitus and peripheral neuropathy were the most commonly encountered comorbidities associated with hypertension. Age !65 years old (P = 0.008), physical inactivity (p<0.001), chat chewing (P<0.001), adding salt to food (P<0.001), and coffee use (P<0.001) are significantly associated with uncontrolled BP In a univariate logistic regression analyses. Based on our finding, we recommend Jimma University Specialized Hospital and Federal Ministry of Health of Ethiopia to devise strategies to provide education to hypertensive patients on dietary approach to stop hypertension (DASH) and medication adherence, develop hypertension management clinical practice guidelines and involve dedicated senior physicians and clinical pharmacists at hypertension clinic for better treatment and care of hypertensive patients.