1. Closing the "doughnut hole" has helped protect millions of Medicare beneficiaries from high drug costs Author(s): Purvis, Leigh, author Publication: Washington, DC : AARP Public Policy Institute, March 2017 Subject(s): Drug CostsInsurance CoverageMedicare Part D -- economicsCost SavingsDeductibles and CoinsuranceFinancing, PersonalMedicare -- legislation & jurisprudenceHumansUnited StatesUnited States.