Utilization of, and adherence to, drug therapy among medicaid beneficiaries with congestive heart failure

Abstract

Background: Congestive heart failure (CHF) affects 4.8 million adult Americans, particularly those aged >65 years, and has been described as a "new epidemic" due to the high annual incidence of the disease (an estimated 550,000 new cases per year).

Objectives: The goal of this research was to determine the number of Medicaid beneficiaries with CHF, identify the rate of CHF drug use, estimate adherence rates, examine factors associated with CHF drug use and adherence, and explore policy implications of the research findings.

Methods: Methods used included identifying noninstitutionalized beneficiaries with >or=1 inpatient claim or >or=2 ambulatory claims with a CHF diagnosis and claims for CHF drugs using 1998 State Medicaid Research Files and 1999 Medicaid Analytic eXtract data for Arkansas, California, Indiana, and New Jersey. Patient adherence was estimated using the medication possession ratio (MPR) and days of medication persistence. Multivariate regression models were used to identify factors associated with CHF drug use and adherence.

Results: Overall, 84.8% of beneficiaries had claims for at least 1 CHF medication; 15.2% of beneficiaries were not using any CHF medications. Among those with a claim, the mean number of claims per month was 1.4, and 25.8% had >or=4 claims per month. Mean MPR was 71.9% and mean days of medication persistence were 24.8 per month. Persons aged <65 years, men, ethnic minorities, patients with hospital admissions for conditions other than CHF, and beneficiaries with high Chronic Illness and Disability Payment System scores were less likely to have a CHF drug claim and had lower adherence rates.

Conclusions: State Medicaid agencies and Medicare prescription drug plans should consider designing targeted interventions that encourage better adherence among Medicaid beneficiaries with CHF, particularly men, those aged <65 years, ethnic minorities, and patients with poor overall health status.