Medicare Part D Drug Coverage Leads to Increased Use of Antibiotics Among Seniors, GSPH Study Says

Issue Date: 
August 24, 2010
Yuting ZhangYuting Zhang

Improved drug coverage under Medicare Part D has led to an increase in the use of antibiotics by seniors, particularly of brand-name and more expensive drugs, according to a University of Pittsburgh Graduate School of Public Health (GSPH) study. Published in the Aug. 23 issue of Archives of Internal Medicine, the study suggests recent changes in drug coverage improved the use of antibiotics for pneumonia but could lead to unnecessary spending on expensive broad-spectrum antibiotics and the overuse of inappropriate antibiotics. The study is the first to explore spending on antibiotics under Medicare Part D.

“Overuse of antibiotics is a common and important problem that can lead to medical complications and drug resistance,” said lead author Yuting Zhang, a GSPH assistant professor of health economics.

The study included more than 35,000 Medicare beneficiaries and compared their use of antibiotics two years before and after the implementation of Medicare Part D, which reduced out-of-pocket drug spending by between 13 and 23 percent. The study’s authors found that antibiotic use increased most among beneficiaries who lacked drug coverage prior to enrolling in Medicare Part D. Beneficiaries who previously had limited drug coverage also were more likely to fill prescriptions for antibiotics after enrolling in Part D. The largest increases were found in the use of broad-spectrum, newer, and more expensive antibiotics.

Researchers also noted that the use of antibiotic treatment for pneumonia tripled among those who previously lacked drug coverage, which they say is encouraging, given the high mortality associated with community-acquired pneumonia among the elderly. However, they also found increases in antibiotic use for other acute respiratory tract infections (sinusitis, pharyngitis, bronchitis, and nonspecific upper respiratory tract infection) for which antibiotics are generally not indicated.

“When drug coverage is generous, people are more likely to request and fill prescriptions for antibiotics, which may lead to misuse,” Zhang said. “Although many interventions have helped curb antibiotic prescribing for acute respiratory tract infections and other conditions, our study indicates there may still be substantial room for improvement through education and changes in reimbursement practices to reduce inappropriate use of these drugs.”

The study was funded by the National Institutes of Health and the Agency for Healthcare Research and Quality. Coauthors include Bruce Y. Lee, an assistant professor of medicine and biomedical informatics in Pitt’s School of Medicine, and Julie M. Donohue, an assistant professor in GSPH’s Department of Health Policy and Management.