Patients who moved from no drug coverage to Medicare Part D drug coverage increased their use of medications deemed Drugs to Avoid in the Elderly (DAE) from 15.72% to 17.61%.

However, the proportion of DAE in overall drug use declined slightly from 3.01% to 1.98%, according to a new study.

The proportion of drug-disease interactions remained stable. Medicare Part D, implemented in 2006, brought drug coverage to 28 million beneficiaries who either lacked it previously or had higher out-of-pocket costs, increased prescription drug use, and resulted in greater adherence to drug treatment for chronic diseases.

The researchers suggest that to maximize the potential for Part D to improve the quality of medication use among older adults, additional changes to pharmacy benefit design (e.g., cost sharing) and health professional education may be necessary.

More details are in Donohue et al. (2012). Medicare Part D and potentially inappropriate medication use in the elderly. The American Journal of Managed Care, 18(9), e315-e322.