Nonadherence to angiotensin-converting enzyme inhibitors and/or angiotensin II receptor blockers among high-risk patients with diabetes in Medicare Part D programs

Abstract Objectives To identify predictors of nonadherence to angiotensin-converting enzyme inhibitors (ACEIs) and/or angiotensin II receptor blockers (ARBs) and to assess the association between nonadherence to ACEIs/ARBs and potentially avoidable hospitalizations (PAHs) among elderly high-risk patients with diabetes. Methods Medicare Part D enrollees from six states who had diabetes and coexisting hypertension and/or renal disease, were aged 65 years or older, and who had filled at least one prescription for ACEIs/ARBs in the first 6 months of 2006 were included in this retrospective cohort study. The primary outcomes of interests were patient nonadherence to ACEI/ARB therapy, which was defined as a proportion of days covered (PDC) less than 0.8 and PAH for diabetes during the patient follow-up period (July 1, 2006, to March 31, 2007). Results A total of 599,141 patients (mean [±SD] age 75.6± years, 66% women, 63% white, 15% black, and 9% Hispanic) were included. Among them, 46% were nonadherent to ACEI/ARB therapy and 6.3% had a PAH during the follow-up period. In multivariate logistic regressions, patients with diabetes and both hypertension and renal disease and patients with diabetes and renal disease only were 24% and 15% more likely, respectively, to be nonadherent to ACEI/ARB therapy compared with patients with diabetes and hypertension. Black and Hispanic patients were also more likely to be nonadherent to ACEI/ARB therapy. Nonadherence to ACEI/ARB therapy was associated with a 5% increase in the likelihood of PAH. Conclusion Adherence to ACEI/ARB therapy is suboptimal among elderly high-risk patients with diabetes enrolled in Medicare Part D programs from six states, and nonadherence to ACEIs/ARBs is associated with a slightly increased risk for PAH.