Underutilization of cardiovascular medications by aged Medicare beneficiaries with heart disease

Abstract

Despite publication of evidence-based guidelines and numerous quality-improvement efforts, studies have documented under use of effective cardiovascular medications in a large proportion of elderly patients with heart disease. This study has two objectives. The first is to examine utilization of effective cardiovascular medications for four common conditions among a nationally representative sample of institutionalized and community-dwelling aged Medicare beneficiaries. These include: warfarin in atrial fibrillation, beta-blockers in myocardial infarction, statins in hyperlipidemia and coronary artery disease, and ACE-inhibitors in diabetes with concomitant cardiovascular risk factors. The second aim is to assess policy-relevant risk factors associated with under use of these cardiovascular medications; specifically, to examine whether the risk of under treatment varies with the presence, type, and generosity of drug coverage; beneficiary age; physician specialty; geographic location; and type of residential setting. The study also examined whether the risk of under treatment of elderly beneficiaries has decreased over time. The data source was the Medicare Current Beneficiary Survey (1997--2000) supplemented with data from Medicare claims. Descriptive as well as multivariate analyses were conducted. Propensity score techniques were used to compare underuse between community and nursing home residents. Substantial underuse of cardiovascular medications was found across the four diseases. While the use of these medications in the outpatient setting has increased between 1997 and 2000, there still remains ample opportunity for improvement. Older age was negatively associated with cardiovascular medication use across the disease samples. Type and generosity of prescription coverage was correlated with use of the expensive statins and ACE-inhibitors/ARBs, and uncorrelated with use of the cheaply available warfarin and beta-blockers. Significant geographic variation was observed in all four cardiovascular medications. No significant differences were observed in cardiovascular medication use among patients treated by generalists versus cardiac specialists. Similarly, the risk of under treatment was the same in nursing homes and in the community. These findings point towards the need for increased educational efforts directed toward the physicians as well as patients. The findings relating to prescription coverage have direct implications for the Medicare drug benefit design. Overall, the results of this study can provide guidance to researchers, policy makers, and clinicians concerned with improving the quality of cardiovascular medication use among aged Medicare beneficiaries with heart disease.