Effect of adherence to antihypertensive medication on stroke incidence in patients with hypertension: a population-based retrospective cohort study

OBJECTIVE High blood pressure is a modifiable risk factor for stroke, but non-adherence to antihypertensive medication is a growing concern for healthcare providers in controlling blood pressure. This study aimed to investigate the effect of adherence to antihypertensive medication on stroke incidence. DESIGN Retrospective cohort study. SETTING We analysed National Health Insurance claim data and check-up data from 2009 to 2013. PARTICIPANTS 38520patients with hypertension were defined as those diagnosed with hypertension and prescribed antihypertensive medication. INTERVENTIONS No interventions were made. OUTCOME MEASURE Poisson regression analysis using generalised estimating equations models was performed to examine the association between adherence to antihypertensive medication and stroke incidence. RESULTS Among 38 520 patients with hypertension, 957 (2.5%) strokes occurred during the study period. Non-adherence to medication was significantly associated with a higher risk of stroke (intermediate adherence: adjusted relative risk (aRR)=1.13, 95% CI=1.06 to 1.21; poor adherence: aRR=1.27, 95% CI=1.17 to 1.38). CONCLUSIONS Non-adherence to antihypertensive medication in patients with hypertension was associated with an increased risk of stroke. Therefore, healthcare providers need to focus on interventional strategies to ensure that these patients adhere to medication therapy and to provide continuing support to achieve long-term adherence, ultimately minimising negative health outcomes.