In addition to the traditional FFS Medicare or Medicare Managed Care (MMC) insurance, many elderly buy supplemental insurance policies to cover prescription drugs or catastrophic expenses. These supplemental policies are known as MediGap plans, because they help fill gaps in the available health insurance coverage. Some Medicare beneficiaries are dual eligibles – covered by both Medicare (health insurance for the aged) and Medicaid (health insurance for the poor with chronic disabilities or endstage renal disease). Dually eligible beneficiaries receive prescription drug coverage as part of their Medicaid insurance. During the period of this study (1998–2000) beneficiaries with FFS Medicare did not have any prescription drug coverage unless they had purchased supplemental insurance. About half.
