Prevalence of non-adherence to antihypertensive medication in Asia: a systematic review and meta-analysis

Background Hypertension and its associated complications are one of the leading causes of morbidity and mortality in Asia. Racial disparities in terms of treatment outcomes among hypertension patients have been reported in literature with Asian patients resulting in poorer treatment outcomes. Non-adherence to antihypertensive therapy is frequently associated with poor treatment outcomes. Aim of the review The aim of this review was to estimate the prevalence of non-adherence to antihypertensive medications among patients with hypertension residing in Asia. Method PubMed, Google Scholar, MEDLINE, Embase, Scopus, CINHAL and Cochrane library were searched for studies published between 2000 and 2019 involving hypertensive patients. Studies investigating the prevalence of medication non-adherence in Asian countries, rated either good or fair on National Institute of Health quality assessment tool and published in English language were included in our review. Data were extracted by one author and checked by another using a structured and pilot-tested data extraction sheet. A random-effects meta-analysis was performed using STATA version 14.3®. Results Sixty-Six studies from 22 Asian countries including 2,532,582 hypertensive patients were included. Mean (± SD) age of participants was 58(± 6) years. Overall, the estimated prevalence of non-adherence to antihypertensive medication in Asia was 48% (95% CI: 41–54, P = 0.001). The rate of non-adherence was higher among females 49% (95% CI: 41–56, P = 0.001) compared to males 47% (95% CI: 40–53, P = 0.001). As per the region, the highest prevalence of non-adherence was found in South Asia 48% (95% 44–51, P = 0.877) followed by East Asia 45% (31–59, P = 0.001) and the Middle East 41 (95% 30–52, P = 0.001). Similarly, higher rate of non-adherence was observed in low and lower middle-income countries i.e. 50% (95% CI: 47–54, P = 0.220) as compare to upper-middle and high-income countries i.e. 37% (95% CI: 25–49, P = 0.001) and 44% (95% CI: 29–59, P = 0.001) respectively. Conclusion The prevalence of non-adherence to antihypertensive medication is high in Asia. This may partly explain poor treatment outcomes and incidence of higher mortality rate in Asia frequently reported in the literature. There is a need to implement appropriate policies and clinical practices to improve medication adherence.