Effect of characteristics of pharmacotherapy on non-adherence in chronic cardiovascular disease: A systematic review and meta-analysis of observational studies

IntroductionCardiovascular medications are effective in prevention of cardiovascular diseases (CVD); however, medication non-adherence contributes to morbidity and mortality. ObjectiveThis systematic review and meta-analysis aims to summarise the evidence regarding the relationship between characteristics of drug therapy (pharmacotherapy) and medication non-adherence in the CVD population. MethodsSystematic searches in PubMed, LILACS, Academic Search and CINAHL databases for observational studies that enrolled adults with CVD were performed, from January 1960 to December 2015. The meta-analysis tested the association between characteristics of pharmacotherapy and self-reported medication non-adherence outcome, using a random effects model. To investigate heterogeneity, we performed subgroup analysis and sensitivity analysis. ResultsTwenty-four cross-sectional studies and 7 cohort studies were included in this review. Based on 31 studies including 27441 participants, we performed meta-analyses for all the characteristics of drug therapy that at least 2 studies evaluated, with a total of fourteen meta-analyses. The pooled results showed that studies which evaluate whether participants have insurance or another program that assists with medication costs, but not full coverage (OR=0.63; 95% CI: 0.53-0.74; P<.001; I-2=0%, P=.938), and a dosing frequency of twice or more daily (OR=1.38; 95% CI: 1.13-1.69; P<.001) were associated with non-adherence. Conclusions and relevanceThe results of this review suggest that access to insurance or another program that assists with medication costs was a protection factor for non-adherence. On the other hand, a high frequency of dosing was a risk factor for non-adherence. Therefore, these characteristics of pharmacotherapy must be considered to improve medication adherence among CVD patients.