“…Systematic random sampling was the main sampling technique which was used by six studies, 20,26,[28][29][30]32 , while six studies were included all adult hypertensive patients visiting the chronic follow-up clinic during data collection. 19,21,22,24,25,27 Face-to-face interviews with chart review were the main data collection technique used by eight studies 19 -21,23,25,26,28,30 while five studies 22,24,29,31,32 used interview (non-specific) technique and only one study 27 used self-administered questionnaires to assess adherence. The overview of the baseline characteristics of the 14 studies are presented in Table 1 (author, region, publication year, study design, study population, sample size, sampling technique, and data collection methods).…”