Medicare Part D Implementation and Associated Health Impact Among Older Adults in the United States.

This study examined the effect of Medicare (Part D) implementation on health outcomes among U.S. older adults. Study participants were initially extracted from the 2004-2008 Health and Retirement Study (HRS). Data from respondents who further participated in the HRS 2005-2007 Prescription Drug Study were analyzed (N = 746). This was a retrospective pre-post design with a treatment and a control group. The difference-in-differences approach with panel ordered logistic regressions was used to examine the Part D effect on three patient health outcomes before and after the implementation, controlling for patient sociodemographic characteristics. People with continuous Part D enrollment from 2006-2008 were less likely to have a worse self-rated health than those who were not enrolled in Part D (odds ratio [OR] = 0.48; p < .05). A higher Charlson Comorbidity Index score was associated with a higher likelihood of having worse self-rated overall health, worse mental health, and worse activities of daily living impairment (ORs = 1.12, 1.17, and 1.36, respectively; all ps < .001). The Part D implementation appears to have a positive effect on older adults' overall health outcomes. A decrease in out-of-pocket cost for health care may encourage older adults to utilize more needed medications, which in turn helped maintain better health.