Impacts of medication non-adherence to major modifiable stroke-related diseases on stroke prevention and mortality: a meta-analysis

BACKGROUND: Medication adherence is one of the crucial attempts in primary stroke prevention. The available evidence lacks comprehensive reviews exploring the association of medication adherence with stroke prevention. OBJECTIVES: To investigate the effects of non-adherence to medications used to treat the modifiable risk of diseases on stroke-associated outcomes in primary stroke prevention. METHODS: Study records were searched from PubMed, Embase, and CINAHL. Those studies reported risks relevant to stroke-associated outcomes and medication non-adherence for patients diagnosed with four modifiable stroke-related diseases (atrial fibrillation [AF], hyperlipidemia, hypertension, and type 2 diabetes mellitus) but without stroke history were included for meta-analysis and further subgroup, sensitivity, and publication bias analyses. A random effect model was performed to analyse the pooled risk estimates of relative risk (RR) and 95% confidence intervals (CIs). RESULTS: Thirty-nine studies (with 2,117,789 participants in total) designed as cohort or case-control studies were included. Those patients presenting with four stroke-related diseases and categorised as medication non-adherent tended to result in stroke and/or associated death (all pooled RR ≥ 1 and 95% CI did not include 1). The findings of stratification and sensitivity analysis for each stroke-related disease showed a similar trend. Non-adherent patients with AF were prone to stroke occurrence (RR 1.852; 95% CI 1.583-2.166) but inclined to reduced bleeding (RR 0.894; 95% CI 0.803-0.996). The existence of publication bias warrants further interpretation. CONCLUSIONS: Non-adherence to medications for the four stroke-related diseases contributes to the development of stroke and/or mortality in primary stroke prevention. More efforts are needed to improve patients' medication adherence.