 It was also found that there were no significant changes in trends in the dual eligibles' out-of-pocket expenditures, total monthly expenditures, pill-days, or total number of prescriptions due to Part D.

A 2020 study found that Medicare Part D led to a sharp reduction in the number of people over the age of 65 who worked full-time.The authors say that this is evidence that before the change, people avoided retiring in order to maintain employer-based health insurance.The federal government is not permitted to negotiate Part D drug prices with drug companies, as federal agencies do in other programs.