Prevalence of medication adherence in patients with hypertension in Iran: A systematic review and meta-analysis of studies published in 2000-2018

BACKGROUND: Medication adherence (MA) has a crucial role in controlling of hypertension (HTN). A difference was observed in the prevalence of anti-hypertensive MA reported in different studies in Iran, so we aimed to determine the overall prevalence of MA. METHODS: Using the English and Persian keywords extracted from Mesh, the databases of MagIran, Barakat Knowledge Network System, Scientific Information Database (SID), Web of Sciences, PubMed, Science Direct, and Google Scholar were reviewed from 2000 to 2018. The overall prevalence of MA was estimated using Random effect mode. The I 2 and Egger’s tests were used to assess heterogeneity and publication bias, respectively. Meta-regression and subgroup analysis were conducted based on variables such as age, marital status, regions, and tools. RESULTS: The overall prevalence of MA was 33%. Moreover, the prevalence of MA based on ‎the 8-Item Morisky Medication Adherence Scale‎ (MMAS-8), Hill-Bone Medication Adherence (HBMA) scale, researcher-made tools, and self-care tools, were 13%, 34%, 48%, and 47%, respectively. A higher MA prevalence (38%) was observed among older adults compared to other age groups, and married patients (32%) compared to single (23%) individuals. The highest MA prevalence (50%) was related to region 5 of the country. Meta-regression results showed a significant relationship between the used tools and MA prevalence. CONCLUSION: The overall prevalence of MA is low in Iran. Furthermore, MA was measured using different questionnaires, such as standard international scales and researcher-made tools. It is proposed that a standard international questionnaire should be used in future studies.