Interventions to improve medication adherence in coronary disease patients: A systematic review and meta-analysis of randomised controlled trials

Background Adherence to multiple cardiovascular (CV) medications is a cornerstone of coronary heart disease (CHD) management and prevention, but it is sub-optimal worldwide. This review aimed to examine whether interventions improve adherence to multiple CV medications in a CHD population. Design This study was based on a systematic review and meta-analysis according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. Methods Randomised controlled trials were identified by searching multiple databases and reference lists. Studies were selected if they evaluated interventions aiming to improve adherence to multiple CV medications targeting a CHD population and if they provided an appropriate measure of adherence. Interventions were classified as complex or simple interventions. Odds ratios (ORs) were calculated and pooled for a meta-analysis. Risk of bias, heterogeneity and publication bias were also assessed. Results Sixteen studies (10,706 patients) were included. The mean age was 62 years (standard deviation (SD) 3.6) and 72% were male. In a pooled analysis, the interventions significantly improved medication adherence (OR 1.52; 95% confidence interval (CI) 1.25-1.86; p < 0.001) and there were no significant differences based on intervention type (complex vs simple), components categories and adherence method. There was moderate heterogeneity (I²= 61%) across the studies. After adjusting for publication bias, the effect size was attenuated but remained significant (OR 1.35; 95% CI 1.09-1.68). Conclusion Interventions to improve adherence to multiple CV medication in a CHD population significantly improved the odds of being adherent. Simple one-component interventions might be a promising way to improve medication adherence in a CHD population, as they would be easier to replicate in different settings and on a large scale.