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 GSPH study. Published in the August 23 issue of Archives of Internal Medicine and the first to explore spending on antibiotics under Medicare Part D, 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.
“Overuse of antibiotics is a common and important problem that can lead to medical complications and drug resistance,” said the study’s lead author, Yuting Zhang, PhD, assistant professor of health economics at GSPH. “One of the key questions we sought to answer with our study is how improved prescription drug coverage under Part D affects the usage of these drugs.”
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 between 13 and 23 percent. They 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 non-specific 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,” said Zhang. “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. Co-authors include Bruce Y. Lee, MD, and Julie M. Donohue, PhD, both of GSPH.