Adherence to Antihypertensive Medication and Incident Cardiovascular Events in Young Adults With Hypertension

Treatment and control rates for high blood pressure are unsatisfactory in young adults. Adherence to pharmacological treatment is alarmingly low, with absence of data on its consequences in young adults with hypertension. We investigated the association of antihypertensive medication nonadherence with incident cardiovascular events among young adults initiating pharmacological treatment for hypertension. From a nationwide health insurance database, we included 123 390 participants (75.1% male) of age 20 to 44 years, free of prior cardiovascular disease (CVD), who initiated pharmacological treatment for hypertension from 2004 through 2007. Participants were categorized as either adherent (proportion of days covered ≥0.8; n=45 350) or nonadherent (proportion of days covered <0.8; n=78 040) to antihypertensive medication during the first year of treatment. The primary outcome was composite CVD events, including myocardial infarction, stroke, heart failure, and cardiovascular death. Over a median follow-up of 10 years, 3002 new CVD events occurred. CVD incidence rates per 100 000 person-years were 191.0 in the adherent group and 282.1 in the nonadherent group. Multivariable-adjusted hazard ratio for CVD events associated with nonadherence versus adherence was 1.57 (95% CI, 1.45–1.71). There was a dose-response association between medication adherence (in quartiles or continuous proportion of days covered) and CVD risk. In conclusion, among young adults who initiated pharmacological treatment for high blood pressure, poor medication adherence was associated with higher risk for future CVD events.