Health system barriers and facilitators to medication adherence for the secondary prevention of cardiovascular disease: a systematic review

Background: Secondary prevention is cost-effective for cardiovascular disease (CVD), but uptake is suboptimal. Understanding barriers and facilitators to adherence to secondary prevention for CVD at multiple health system levels may inform policy. Objectives: To conduct a systematic review of barriers and facilitators to adherence/persistence to secondary CVD prevention medications at health system level. Methods: Included studies reported effects of health system level factors on adherence/persistence to secondary prevention medications for CVD (coronary artery or cerebrovascular disease). Studies considered at least one of beta blockers, statins, angiotensin-renin system blockers and aspirin. Relevant databases were searched from 1 January 1966 until 1 October 2015. Full texts were screened for inclusion by 2 independent reviewers. Results: Of 2246 screened articles, 25 studies were included (12 trials, 11 cohort studies, 1 cross-sectional study and 1 case-control study) with 132 140 individuals overall (smallest n=30, largest n=63 301). 3 studies included upper middle-income countries, 1 included a low middle-income country and 21 (84%) included high-income countries (9 in the USA). Studies concerned established CVD (n=4), cerebrovascular disease (n=7) and coronary heart disease (n=14). Three studies considered persistence and adherence. Quantity and quality of evidence was limited for adherence, persistence and across drug classes. Studies were concerned with governance and delivery (n=19, including 4 trials of fixed-dose combination therapy, FDC), intellectual resources (n=1), human resources (n=1) and health system financing (n=4). Full prescription coverage, reduced copayments, FDC and counselling were facilitators associated with higher adherence. Conclusions: High-quality evidence on health system barriers and facilitators to adherence to secondary prevention medications for CVD is lacking, especially for low-income settings. Full prescription coverage, reduced copayments, FDC and counselling may be effective in improving adherence and are priorities for further research.