We conducted descriptive Cross-sectional design from April to May 2012.
The study was conducted in three District hospitals in Dar es Salaam Region: Amana, Mwananyamala and Temeke hospitals which are located in Ilala, Kinondoni and Temeke Municipalities respectively. The study sites were chosen because majority of hypertensive patients who are diagnosed from dispensaries and health centres are referred to these hospitals for expertise and availability of antihypertensive drugs.
The study population included patients with hypertension, who were using antihypertensive treatment and attending at Amana, Temeke and Mwananyamala hypertension clinics.
Sample size and sampling procedure
Sample size: sample size estimated were 135 calculated using kish and Leslie formula (1965).
n = Z² p(1-p)/ e². The prevalence used was 34% compliance  in Temeke- Dar es Salaam
Simple random sampling was used to select study participants. The researcher established a sampling list from patients attended hypertensive clinics to the respective study hospitals to obtain eligible participants who fit inclusion criteria. There were pieces of paper that were written YES or NO, the word YES was used to represent the targeted study population, and NO was used to represent the population that was not going to participate in the study. The procedure of drawing papers from the box by each study participant was used. Once the piece of paper was chosen, it was not included in the sample again and each participant was allowed to pick only once.
The inclusion criteria and Exclusion criteria
All patients aged 18 years and above with a diagnosis of hypertension for at least one month with or without other co-existing medical conditions and consent to participate in the study. Participants who have been taking antihypertensive treatment for at least one month ago before the beginning of the study were included in the study.
All patients who had not started antihypertensive and could not respond eg too sick to be interviewed were excluded from the study.
Measures of outcome
The outcome variable was treatment compliance, which comprised of medication regimen compliance and lifestyle modification. Medication regimen compliance was composed of 8 items, asking how often you forget to take your medicine. The responses were measured on a 4-point Likert scale: (1) Every day (2) frequently (3) rarely or (4) never. For life style compliance was having 5 items, participants were asked to respond to the single question based on a 4-point Likert scale: how often do desirable or undesirable behaviors related to control of hypertension. The responses were: (1) Every day (2) frequently (3) rarely or (4) never. Some questions were set such that the highest score did not reflect the worst scenario of none-compliance. To resolve these scores were reversed. Example, how often do you engage in physical exercise (4) every day, (3) frequently, (2) rarely or (1) never? The 13 items measuring treatment compliance and life style compliance were added up to get sum index with a distribution ranging from 33 to 52 with mean 44.2963 (SD =3.32578), the median split was used (44.4), which was dichotomized into two groups i.e. 0 = those who are non-treatment compliant and 1 = treatment compliant which was 34-43 and 44-51.
The HBM variables were measured as described below. Perceived severity of having hypertension, perceived susceptibility of being at risk of hypertension complications and perceived benefit were each measured by six items. The reminders (cues to action) were measured by seven items. Participants were then asked to respond: (1) strongly agree, (2) agree, (3) disagree or (4) strongly disagree.
Six items measuring perceived severity were added up to get sum index with a distribution ranging from 7 to 24 with mean 20.10 (SD =2.85), the median split 50.4 was used as a cut point. Dichotomization was done into two frequency groups, those who had low perceived severity and those who had high perceived severity. Six items measuring perceived susceptibility were added up to get sum index ranging from 6 to 19 with mean of 10.79 (SD =2.83), the median split was 49.6. The sum index for perceived susceptibility was dichotomized into 1=, those with low perceived susceptibility and 2= those with high perceived susceptibility.
Six items measuring perceived benefit were added up to get sum index with a distribution ranging from 12 to 24 with mean (SD) 20.24(2.87) median split 51.1, then dichotomized into, those with low perceived benefit and those with high perceived benefit. Seven items measuring cues to action were added up to get sum index with a distribution ranging from 15 to 28 with mean (SD) 24.27(2.65) median split 42.2, then dichotomized into two frequency groups those with low perceived cues to action and those with high cues to action.
Five items measuring perceived barriers were added up to get sum index with a distribution ranging from 5 to 15 with mean (SD) 8.36 (2.48), median split 54.8, then dichotomized into, those with low perceived barrier and those with high perceived barrier. The aspects that might hinder respondents to comply with their treatment included not having enough time to do exercise. Responses were (1) strongly not a problem (2) not a problem (3) problem and (4) strongly a problem.
Frequency distributions were done then bivariate analysis using chi-quire and Pearson correlation between HBM variables were done. Multiple linear regressions were done with treatment compliance as the outcome variable (behavior) and the rest of HBM variables as predictors of the behavior.
Data entry and analysis
Data were entered into the computer using SPSS software programme 17.0 version. Data were cleaned before being subjected to analysis. Data analysis was performed using SPSS software programme. Information was summarized using frequency tables and cross tabulations. The chi-square test was used to compare proportions; bivariate correlation (Pearson correlation) analysis was done. Multivariate analysis was done using Linear Multiple Regression to obtain strongest predictor variable between variables of HBM. A P-value of equal or less than 0.05 was considered a statistically significant.
Ethical clearance was sought from the Research and Publication Ethical Committee of the Muhimbili University of Health and Allied Science. The permission to conduct the study was obtained from Municipal Medical Officer In charge of respective municipal. Written informed consent was obtained, for those who cannot read and write was requested to provide their signature by putting thumb print as signature. The participants were free to withdraw from the research at any stage without incurring any consequences