Kidney function and long-term medication adherence after myocardial infarction in the elderly.

BACKGROUND AND OBJECTIVES The association of kidney function with long-term outpatient medication adherence in the elderly remains understudied. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS A cohort of 2103 patients over the age of 65 years enrolled in a pharmacy benefits program after hospital discharge for myocardial infarction was studied. Using linear mixed effects models, the association of baseline kidney function with long-term adherence to recommended medications after myocardial infarction was examined, including angiotensin converting enzyme inhibitors (ACEIs) and angiotensin II receptor blockers (ARBs), β-blockers, and statins. The primary outcome measure was the percentage of days covered as calculated by pharmacy refill data for 12 serial 3-month intervals (totaling 36 months of follow-up). RESULTS Overall long-term adherence to ACEIs/ARBs, β-blockers, and statins was poor. The mean percentage of days covered by 36 months was only 50% to 60% for all three medication classes. Patients with baseline kidney dysfunction had significantly lower long-term ACEI/ARB and β-blocker adherence compared with patients with higher baseline kidney function. Long-term statin adherence did not vary by baseline level of kidney function. CONCLUSIONS Long-term medication adherence after myocardial infarction in the elderly is low, especially in patients with kidney dysfunction. Future strategies to improve medication adherence should pay special attention to the elderly with kidney dysfunction because they may be especially vulnerable to its adverse clinical consequences.