Inuence of dietary and lifestyle factors on blood pressure control among adult hypertensive patients under care in Uganda

Background Hypertension is an important worldwide public-health challenge because of its high prevalence and for being a risk factor for cerebrovascular, cardiovascular and chronic renal disease. Despite these risk factors, blood pressure control among hypertensive patients is still poor. Objectives To assess dietary and lifestyle factors associated with uncontrolled blood pressure control among a series of Ugandan hypertensive patients under care at a Kiruddu hospital. Methods A cross sectional study involving 271 adult hypertensive patients attending general outpatient hypertensive clinic were enrolled. We collected data on dietary and lifestyle factors, social demographics, BMI, comorbidities, and adherence to hypertensive medication. Dietary factors were based on recommended DASH diet including nine food items salt; grains; fruits; vegetables; nut/seeds, and legumes; dairy; meat; fat; and sweets. Questionnaires on alcohol intake, smoking status and level of physical activity were also administered. An average of the previous two Blood pressure readings were recorded while weight and height were measured for each subject at enrolment. Factors associated with uncontrolled blood pressure (>140/90mmHg) were assessed using a multivariate logistic regression model. blood are fortunately modiable.


Introduction
Hypertension is an important worldwide public-health challenge because of its high prevalence and a major risk factor for stroke, ischemic heart disease, congestive heart failure, myocardial infarction, and renal failure among others (Mendis et al., 2005). According to WHO, there are 1.39 billion people living with hypertension representing 31% of the global adult population (1). It is projected that the number of hypertension cases in Sub-Saharan Africa is approximately 80million representing 46% of the world's hypertensive population and this is estimated to increase to 150 million in 2025 (1). In Uganda, the ndings from the National Non-Communicable Diseases Risk Factor Survey have shown an overall prevalence of hypertension of 26.4% (Guwatudde et al., 2015).Control of hypertension still remains minimal in the world despite the existence of clinical guidelines recommended from several trials which dictate; following medication, dietary and exercise regimens, smoking cessation and minimizing alcohol consumption (2,3). Uncontrolled BP accounts for 9.4 million deaths and is responsible for morbidity associated with approximately 54% of strokes, 47% of ischemic heart disease, 25% of other cardiovascular diseases and 7% of global disability-adjusted life years and nearly 10 million deaths per year (4).
Four behavioral risk factors play an important role in the development of hypertension. These include tobacco use, unhealthy diet, physical inactivity and harmful use of alcohol. Other risk factors of hypertension in adults include poor stress management, obesity and having diabetes mellitus (WHO 2013). The main objective in the management of hypertension is to attain an optimal BP to avert morbidities and mortalities associated with raised BP.
Lack of good BP control in more than two-thirds of people living with hypertension has been attributed mainly to poor compliance to therapy including dietary and lifestyle modi cation. There are limited data on the prevalence of BP control yet populations could bene t from control efforts (5).
Given that populations in low and middle countries are especially being affected through engagement in easily modi able risk factors like unhealthy diet, tobacco use, harmful use of alcohol and physical inactivity, this study therefore aimed at quantifying the proportion of patients who had uncontrolled blood pressure and to identify dietary, lifestyle and clinical factors associated with BP control among hypertensive patients under care at Kiruddu hospital.

Ethical permission
Ethical clearance was sought from higher Degrees Research and Ethics Committees of Makerere University prior to implementation of the research study. Then permission was sought from Mulago hospital IRB and Kiruddu hospital. Written informed consent was obtained from all study participants before enrollment into the study.

Study design
The study employed descriptive cross-sectional design.

Study site
The study was conducted at the outpatient hypertensive clinic of Kiruddu general referral hospital an extension of Mulago National Referral Hospital located in Kampala, the capital city of Uganda. The site was chosen because it receives high number of patients diagnosed with hypertension from different dispensaries, health centers and hospitals all over the country. This outpatient clinic sees approximately 100 individuals with hypertension per week.

Recruitment of study participants
Participants were eligible if they were 18 years or older with known diagnosis of hypertension presenting at Kiruddu hypertensive outpatient clinic at least for the second time at the time of the study.
Participants were excluded if their data of previous BP readings were not available. Participants who met the eligibility criteria represented the target study population. Consecutive sampling was used as participants were recruited as they came for each clinic day until the required sample size was achieved.

Study Variables
Trained Research Assistants collected data on dietary and lifestyle factors, social demographics and clinical factors. Social demographic information included age, gender, marital status, education attainment and occupation. Dietary patterns of the study participants were assessed basing on the recommended DASH diet using food frequency questionnaire of the foods consumed in the last one month including salt; grains; fruits; vegetables; nut/seeds, and legumes; dairy; meat; fat; and sweets. (6). Clinical factors assessed included Body mass index, comorbidities, and adherence to hypertensive medication. Adherence was assessed using the Morisky adherence scale (MMAS-8). It is an eightquestion scale with Yes=0 or No=1 answers where a score of ≥ 6 is termed as good adherence while a score of < 6 is termed as poor adherence. (7).
Study participants were also interviewed on their lifestyle behaviors such as alcohol use, cigarette smoking, and level of physical activities. Alcohol consumption was de ned as 'drinker' and 'non-drinker.' Quantity of alcohol consumed by current drinkers was classi ed according to how many bottles they drink per week in the past month. Greater than 2 standard drinks for men or greater than 1 drink for woman of local alcohol or imported alcoholic beverages per day (1 standard drink is equal to 14 grams of pure alcohol found in 1 regular beer) (8). Cigarette smoking status was de ned as never, former, or current smoker. current smokers were those who were currently smoking while former smokers were those who had ever smoked in the last ve years but were no longer smoking. Smoking was classi ed as taking any form and number of cigarettes.
Physical activity was assessed by asking participants if they are involved in either vigorous exercise (lifting heavy loads, digging, construction work), moderate exercise (brisk walking, carrying light loads, riding a bicycle and recreational activities like physical exercises and walking during leisure) or no exercise. Participants who spent at least 30 minutes/day of moderate-intensity activities 5 days a week and those who spent at least 10 minutes/ day of vigorous physical activities 5 days a week ful lled WHO minimum recommendations for physical activity (9). Those who did not meet the above criteria were classi ed as those with no exercise. Current Blood pressure measurements were performed by trained study nurses following a standardized study protocol. Each study participant rested for at least 5 minutes prior to blood pressure measurements while sitting in a chair with both feet at on the oor. Both arms were supported at the level of the heart on a table. To ascertain blood pressure control, we undertook document review of patient's les and recorded two recent BP readings measured in the previous four months. The average of the previous and current BP reading was used as the overall BP reading.
Anthropometric evaluations including measurement of weight and height were performed by Study nurses. Weight was measured using a pre-calibrated Secca scale with participants wearing light clothing and barefooted. Weight was rounded off to the nearest 1kg. Height was measured with the participant standing upright against a wall using a previously a xed height measuring device. Body mass index (BMI) of each participant was then derived by dividing weight in kilograms with height in meters squared (kg/m 2 ). This was divided into four categories underweight <18.5kg/m 2 , Normal weight 18.5-24.99kg/m 2 , Overweight 25-29.99kg/m 2 and Obese ≥30kg/m 2 (10).

Background characteristics of study participants
Overall, 271 respondents participated in the study. Their mean age was 57 (SD = 0.76) years which ranged from 22 to 86 years. Most of the respondents were females 211 (77.9%), 145 (53.5%) were currently married and 103 (38.0%) identi ed themselves as Catholics. As shown in Table 1, about 43% (117) were unemployed, 127 (46.9%) attained at least secondary level education and close to threequarters (75.7%) were urban dwellers. Eighty-three (30.6%) of the respondents had been diagnosed with hypertension for more than 10 years while only 48 (17.7%) had the disease for less than two years.

Social demographic characteristics of participants with uncontrolled versus controlled BP
The mean systolic and diastolic BP readings were 146.0mmHg (95% CI: 142.0, 149.0) and 66.4mmHg (95% CI: 99.8, 135.2) respectively. The overall proportion of uncontrolled BP was 44.7% (95% CI: 38.7, 50.6%). There was no statistically signi cant difference between uncontrolled and controlled BP in terms of sex, age, marital status, religion, rural residence, level of education, employment status and duration with hypertension as shown in Table 1.
However, participants whose blood pressure were not controlled were more likely to reside in rural dwellings and have no formal education.  Inadequate consumption of fruits and vegetables had twice the odds of uncontrolled BP compared to adequate consumption (p=0.000 and p=0.005) respectively. Also, participants who consumed sh less than two servings a week were more likely to have uncontrolled BP (p=0.014). Participants who consumed red meat in a week were more likely to have uncontrolled BP as compared to those who did not, though the differences were not statistically signi cant (p=0.137).
Among the lifestyle habits of participants, smoking and inadequate physical activity were associated with uncontrolled BP while alcohol consumption had no association with BP control status. The categories "formerly smoked" and "current smoker" were merged due to low frequencies (n=14 and n=2, respectively) and this category was found to be associated with uncontrolled BP (p=0.044). There were higher percentages of no physical activity in the uncontrolled BP group (6.0%) compared to the controlled BP group (48.8%). Inadequate physical activity had 1.7 odds of uncontrolled BP compared to adequate physical activity and the difference between these groups was statistically signi cant (p=0.030). See Table 2. Study participants with good adherence were more likely to have controlled BP levels (74.4% of patients with controlled blood pressure had good adherence levels). The odds of having uncontrolled BP among poor adherent participants were 2.61 compared to those who were fully adherent (p<0.000).
Slightly higher percentages of participants in the uncontrolled BP group had heart problems and diabetes (32.0%), (37.0%), compared to those in the controlled group (28.1%), (34.7%) respectively. However, the differences found between these groups were not statistically signi cant. Table 3  Factors associated with blood pressure control among hypertensive patients  (p=0.192). Similarly, participants who did not adhere to their anti-hypertensive medication were 1.82 times more likely to have uncontrolled BP compared to those who adhered to their medication (AOR=1.82, 95% CI: 1.03-3.21, p=0.039). Although religion, place of residence, level of education, eating vegetables less than 7 days/week, consumption of sh less than two serving a week, consumption of red meat every week, smoking and inadequate physical activity was strongly associated with blood pressure control in unadjusted analysis, the effects were moderated into non-signi cance in adjusted analysis.

Discussion
The results showed that almost half of the participants had uncontrolled BP (44.7%) The dietary and lifestyle factors associated with this problem were consumption of raw salt, and inadequate fruit intake while clinical factors included being overweight and non-adherence to prescribed antihypertensive medication.
Controlling BP in people with hypertension to reduce cardiovascular morbidity and mortality is a major challenge and a public health problem in many developing countries including Uganda. This study revealed that 44.7% of hypertensive patients had uncontrolled BP despite being on follow up and under care at Kiruddu hospital. This nding coincides with studies in Ethiopia (42.9%) and France (47%) where high levels of uncontrolled BP were reported (11,12). However, this study had a much higher prevalence than that seen in a Korean study of 15.6% (13).
Despite the high prevalence seen in this study, some studies in other countries like Ethiopia (52.7%), Ghana (57.7%) and Singapore (75.9%) had a much higher uncontrolled BP percentage. (14)(15)(16)(17). This might be due to the difference in the study population (community vs hospital-based study, elderly vs general population) and lifestyle behaviors such as feeding habits and sedentary lifestyles that bring hypertension di cult to control.
Another study conducted in central Kenya among hypertensive patients indicated that the level of poor BP control was as high as 66.4% compared to the nding of this research, and this could be because single BP measurements were taken in Kenya in contrast to this study which may have led to overestimated prevalence (18).
Although no associations were found for social demographic characteristics such as sex, age and employment status in this study, some previous studies have identi ed a relationship between these factors and having uncontrolled BP (5,(19)(20)(21). Studies have reported an association between increasing age and uncontrolled BP (22), while a study by Teshome DF et al., showed that hypertensive patients older than 60 years were three times more likely to control their BP as compared to the age group of 18-40 years (11). These results could be due to different age categorization, and the high percentages of females (77.9%) in this study suggesting possible gender differences in health seeking behaviors. Similar to our study, age was not associated with uncontrolled BP in a study by Basu and Millett (23).
Rural residence and level of education were not signi cant in this study. However, in the Prospective Urban Rural Epidemiology (PURE) study, better BP control was seen among urban than rural dwellers (24) while in a Ghanaian study, higher rates of uncontrolled BP were seen among urban than rural residents (14).
Dietary factors associated with uncontrolled BP in this study included: inadequate fruit consumption and raw salt consumption. These results are similar to those from a previous study in Ethiopia where the use of top added salt on a plate and failure to consume fruits and vegetables on most days of the week were negatively associated with optimal BP control (11). This may be because high salt intake causes uid retention which increases cardiac burden resulting in high BP.
Despite some studies nding an association with some lifestyle factors, this study did not nd any association with smoking, physical activity and alcohol intake. Increased physical activity was associated with successful BP control in a Korean and Ethiopian studies (11,13). This difference may be due to the low numbers of participants who reported to be current smokers (0.7%).
Overweight and obesity were common among our study subjects (31.7% and 32.5% respectively). This study showed that BP control is poor in overweight patients. Indeed, our nding supports the notion that persistent overweight and obesity can interfere with the e cacy of hypertension drugs, increase peripheral vascular resistance which increases cholesterol and triglyceride levels and decreases HDL levels in the blood, and thereby exacerbate poor BP control (25). This nding is coherent with similar studies in Singapore, Angola and Uganda (26-28) but BMI had no association in a Nigerian study (17,28).
Poor adherence to prescribed anti-hypertensive medication captured by the Morisky Medication Adherence Scale was a key determinant of BP control as expected. This nding is in line with that of previous studies in Ghana and Ethiopia (11,14). Reasons for non-adherence are multi-factorial and are often contributed to by a mix of patient related, physician related and health system-related factors. This makes adherence to therapy for chronic diseases such as hypertension a major challenge worldwide (Brown and Bussell 2010).
Clinical variables that did not show any association with BP control contrary to other studies included duration with hypertension, number of comorbidities, and presence of diabetes. In a study by Myung Hwa Yang et al., patients with comorbidities and high numbers of comorbid diseases showed better BP control achievement rates (13). This difference may be attributed to the use of either patient les or self-reported methods to ascertain if a patient had any other diseases.

Conclusions
The proportion of hypertensive patients with uncontrolled BP among this study population was high (44.7%).
Dietary factors including consumption of raw salt and inadequate fruit consumption were signi cantly associated with uncontrolled BP.
Overweight and poor adherence to antihypertensive medication were the clinical factors signi cantly associated with uncontrolled BP.
As identi ed in this study, many of the factors that impact on the control of blood pressure are fortunately modi able. Researchers should use objective methods to assess dietary habits in order to avoid under or over reporting. In addition, further longitudinal studies that include physical and biochemical measurements to identify variables associated with uncontrolled BP should be carried out.
Further investigation is warranted to assess health professional level of knowledge on hypertension management. There is also a need to explore other factors that have been shown to have an association with BP control status like health system related factors (Brown and Bussell 2010).