Abstract 47: Adherence to Antihypertensive Medications is Associated with Fewer Cardiovascular Related Hospitalizations and ED Visits in Patients 65 and Older

Abstract

Objective To examine the relationship between Antihypertensive Medication (AHM) adherence and subsequent cardiovascular related hospitalizations (CVH) and emergency department visits (CVED) in patients 65+ years of age. Methods A retrospective cohort study of patients 65+ years of age receiving AHM therapy was performed. Patients had deidentified data on medical and pharmacy claims in the Medco Health Solutions, Inc. integrated warehouse, and were continuously enrolled in coverage from January 2009 through June 2011. Medication adherence was assessed by proportion of days covered (PDC) over 1 year, and risk of CVH and CVED over the subsequent year. Patients were segmented into three adherence cohorts based on PDC: 80 to 100% (adherent), 60 to 79% and <60%. Risk of CVH and CVED visits was determined by medical claims during the subsequent 12 months. Results Among the 316,108 total eligible adults, mean age was 74.9 +/-6.1 years; 57.5% were women, 82.4% were hypertensive, 28.3% had coronary artery disease (CAD), 14.1% had stroke, 9.6% had heart failure (HF) and 32.5% had diabetes. A subset that included only Medicare Part D (Med-D) plan participants (n=26,248, mean age 74.3 +/-5.8 years) had a greater percentage of women and comorbidities vs. the non-Med-D patients (n=298,860, mean age 75.0 +/-6.1 years). Comorbidity differences between the Med-D vs. non-Med-D groups were: Women 64.5% vs. 56.8%; hypertension 93.6% vs. 81.4%; CAD 34.8% vs.27.7%; stroke 16.0% vs. 13.9.%; HF 15.4% vs. 9.0%; and diabetes 54.9% vs. 30.5%, p<0.0001 for all groups. Overall, mean PDC was 91% (+/-15%) and was lower in the Med-D group at 89% (+/-17%) vs. non-Med-D group at 91% (+/-14%). The majority, 271,002 (85.7%) had PDC ≥80%; 26,973 (8.5%) had PDC of 60-79% and 18,133 (5.7%) had PDC of <60%. After adjustment for age, sex, comorbidities, year 1 hospitalizations and ED visits, and total medications, the overall risk of CVH was significantly greater with PDC 60-79% (OR 1.23; CI 1.19-1.28) and PDC <60% (OR 1.31; CI 1.25-1.37), p<0.0001 vs. PDC ≥80%. The risk of CVED was increased with PDC 60-79% (OR 1.18; CI 1.12-1.24) and PDC <60% (OR 1.29; CI 1.22-1.37), p<0.0001 vs. PDC ≥80%. Patients covered by Med-D plans with PDC < 60% had the greatest risk of CVH (OR 1.42; CI 1.26-1.59) and CVED (OR 1.49 CI 1.32-1.68). Conclusions For patients 65+ years of age, one in seven was nonadherent to AHM medications. Adherence to AHM was associated with an inverse risk of CVH and CVED. The risk of increased CVH and CVED was even more pronounced in Med-D plan participants with the poorest nonadherence.