Background: Adherence to prescribed medication is an imperative issue which can be directly linked with the management of chronic diseases like hypertension; failure to adhere can affect the effectiveness of medication as well as the efficiency of the health care system. There is scarcity of information regarding the level of drug adherence for antihypertensive medications and its determinants in Ethiopia, particularly in the study area. Therefore, the aim of this study was to assess adherence level and its determinants for antihypertensive medications among adult hypertensive patients attending the chronic illness clinics of the referral hospitals in northwest Ethiopia.
Methods: Institution based cross sectional study was conducted from March to April, 2016. The systematic random sampling technique was used to select 409 study participants from three referral hospitals. The questionnaire was prepared using the World Health Organization (WHO) conceptual model and by reviewing international literature. The data were collected using an interviewer administered questionnaire. The data were entered in to Epi - Info version 7 and then transferred to the statistical package for social science (SPSS) version 20 for data cleaning and analysis. Bivariate analysis was first done to see the association between each independent variables and dependent variable. Variables with a P-value of less than 0.2 in the bivariate analysis were entered in to the multivariate logistic regression model for final analysis. Multivariate analysis was done using Backward logistic regression method. P-value less than 0.05 was considered to determine the statistical significance of the association and odds ratio with a 95% confidence interval was used to determine the presence, strength, and direction of association between covariates (explanatory variables) and the outcome variable. The Morisky medication adherence scale was used to assess the adherence status using > = 6 as adherent or < 6 as non adherent score.
Results: Four hundred and nine (409) study participants were interviewed with a response rate of 100%. The mean age of the respondents was 54.5 years with (Standard Deviation (SD) ± 13.58). The overall rate of good adherence was 67.2% (95% CI = 62.8, 71.6). Participants who had a favourable attitude towards antihypertensive medications (Adjusted odds ratio (AOR) = 9.88, 95% confidence interval (CI): 5.34, 18.27), having good patient- provider relationship (AOR = 4.25, 95% CI: 2.32, 7.86), having one (AOR = 4.36, 95% CI: 1.34, 14.12) or no (AOR = 3.38, 95% CI:1.01,11.31) co-morbidities, a long duration of treatment (AOR = 1.89, 95%CI: 1.07, 3.35), and a low medical cost (AOR = 2.06, 95% CI: 1.13, 3.76) had associations with good drug adherence for antihypertensive medication/s.
Conclusions: The prevalence of good drug adherence for anti-hypertensive medications in this study was high. Prevention of co- morbidities, making medical services accessible, and maintaining good client-provider interaction are of paramount importance for good drug adherence.
Keywords: Antihypertensive medication; Drug adherence; Ethiopia; Hypertensive patients.