Predictors of adherence with antihypertensive and lipid-lowering therapy.

BACKGROUND: Patients with comorbid hypertension and dyslipidemia are at high risk for cardiovascular disease, which can be considerably mitigated by treatment. Adherence with prescribed drug therapy is, therefore, especially important in these patients. This study was undertaken to describe the patterns and predictors of adherence with concomitant antihypertensive (AH) and lipid-lowering (LL) therapy.
METHODS: This retrospective cohort study examined 8406 enrollees in a US managed care plan who initiated treatment with AH and LL therapy within a 90-day period. Adherence was measured as the proportion of days covered in each 3-month interval following initiation of concomitant therapy (mean follow-up, 12.9 months). Patients were considered adherent if they had filled prescriptions sufficient to cover at least 80% of days with both classes of medications. A multivariate regression model evaluated potential predictors of adherence.
RESULTS: The percentage of patients adherent with both AH and LL therapy declined sharply following treatment initiation, with 44.7%, 35.9%, and 35.8% of patients adherent at 3, 6, and 12 months, respectively. After adjustment for age, sex, and other potential predictors, patients were more likely to be adherent if they initiated AH and LL therapy together, had a history of coronary heart disease or congestive heart failure, or took fewer other medications.
CONCLUSIONS: Adherence with concomitant AH and LL therapy is poor, with only 1 in 3 patients adherent with both medications at 6 months. Physicians may be able to significantly improve adherence by initiating AH and LL therapy concomitantly and by reducing pill burden.