Results:

Data were available on 1,978,919 unique participants with 135,627 CVD and 94,126 all-cause mortality events collected over an average follow-up between 1 and 10 years. The average age of the participants was 63.1 years, and 55% of the participants were male. Seventeen studies were based in Europe, 21 in North America, three in Asia-Pacific, and three were conducted in multiple countries. Overall, 60% (95% confidence interval [CI], 52-68%) of included participants had good adherence (adherence ≥80%) to CV medications. The relative risks (RRs) (95% confidence interval) of development of CVD in those with good versus poor (<80%) adherence were 0.85 (0.81-0.89) and 0.81 (0.76-0.86) for statins and antihypertensive medications, respectively. Corresponding RRs of all-cause mortality were 0.55 (0.46-0.67) and 0.71 (0.64-0.78) for good adherence to statins and antihypertensive agents. These associations remained consistent across subgroups representing different study characteristics. Estimated absolute risk differences for any CVD associated with poor medication adherence were 13 cases for any vascular medication, nine cases for statins, and 13 cases for antihypertensive agents, per 100,000 individuals per year.