With the passage of the Balanced Budget Act of 1997, Medicare beneficiaries were formally given the option to receive their Original Medicare benefits through capitated health insurance Part C health plans, instead of through the Original fee for service Medicare payment system. Many had previously had that option via a series of demonstration projects that dated back to the early 1970s. These Part C plans were initially known in 1997 as “Medicare+Choice”. As of the Medicare Modernization Act of 2003, most “Medicare+Choice” plans were re-branded as “Medicare Advantage” (MA) plans (though MA is a government term and might not even be “visible” to the Part C health plan beneficiary). Other plan types, such as 1876 Cost plans, are also available in limited areas of the country. Cost plans are not Medicare Advantage plans and are not capitated. Instead, beneficiaries keep their Original Medicare benefits while their sponsor administers their Part A and Part B benefits. The sponsor of a Part C plan could be an integrated health delivery system or spin-out, a union, a religious organization, an insurance company or other type of organization.
Public Part C Medicare Advantage and other Part C health plans are required to offer coverage that meets or exceeds the standards set by Original Medicare but they do not have to cover every benefit in the same way (the plan must be actuarially equivalent to Original Medicare benefits). After approval by the Centers for Medicare and Medicaid Services, if a Part C plan chooses to cover less than Original Medicare for some benefits, such as Skilled Nursing Facility care, the savings may be passed along to consumers by offering even lower co-payments for doctor visits (or any other plus or minus aggregation approved by CMS).
Original “fee-for-service” Medicare Parts A and B have a standard benefit package that covers medically necessary care as described in the sections above that members can receive from nearly any hospital or doctor in the country (if that doctor or hospital accepts Medicare). Original Medicare beneficiaries who choose to enroll in a Part C Medicare Advantage or other Part C health plan instead give up none of their rights as an Original Medicare beneficiary, receive the same standard benefits—as a minimum—as provided in Original Medicare, and get an annual out of pocket (OOP) upper spending limit not included in Original Medicare. However they must typically use only a select network of providers except in emergencies or for urgent care while travelling, typically restricted to the area surrounding their legal residence (which can vary from tens to over 100 miles depending on county). Most Part C plans are traditional health maintenance organizations (HMOs) that require the patient to have a primary care physician, though others are preferred provider organizations (which typically means the provider restrictions are not as confining as with an HMO). Others are hybrids of HMO and PPO called HMO-POS (for point of service) and a few public Part C health plans are actually fee for service hybrids.
Public Part C Medicare Advantage health plan members typically also pay a monthly premium in addition to the Medicare Part B premium to cover items not covered by traditional Medicare (Parts A & B), such as the OOP limit, self-administered prescription drugs, dental care, vision care, annual physicals, coverage outside the United States, and even gym or health club memberships as well as—and probably most importantly—reduce the 20% co-pays and high deductibles associated with Original Medicare. But in some situations the benefits are more limited (but they can never be more limited than Original Medicare and must always include an OOP limit) and there is no premium. The OOP limit can be as low as $1500 and as high as but no higher than $6700. In some cases, the sponsor even rebates part or all of the Part B premium, though these types of Part C plans are becoming rare.
Before 2003 Part C plans tended to be suburban HMOs tied to major nearby teaching hospitals that cost the government the same as or even 5% less on average than it cost to cover the medical needs of a comparable beneficiary on Original Medicare. The 2003-law payment framework/bidding/rebate formulas overcompensated some Part C plan sponsors by 7 percent (2009) on average nationally compared to what Original Medicare beneficiaries cost per person on average nationally that year and as much as 5 percent (2016) less nationally in other years (see any recent year’s Medicare Trustees Report, Table II.B.1).
The 2003 payment formulas succeeded in increasing the percentage of rural and inner city poor that could take advantage of the OOP limit and lower co-pays and deductibles—as well as the coordinated medical care—associated with Part C plans. In practice however, one set of Medicare beneficiaries received more benefits than others. The MedPAC Congressional advisory group found in one year the comparative difference for “like beneficiaries” was as high as 14% and have tended to average about 2% higher. The word “like” in the previous sentence is key. MedPAC does not include all beneficiaries in its comparisons and MedPAC will not define what it means by “like” but it apparently includes people who are only on Part A, which severely skews its percentage comparisons—see January 2017 MedPAC meeting presentations. The differences caused by the 2003-law payment formulas were almost completely eliminated by PPACA and have been almost totally phased out according to the 2018 MedPAC annual report, March 2018. One remaining special-payment-formula program—designed primarily for unions wishing to sponsor a Part C plan—is being phased out beginning in 2017. In 2013 and since, on average a Part C beneficiary cost the Medicare Trust Funds 2%-5% less than a beneficiary on traditional fee for service Medicare, completely reversing the situation in 2006-2009 right after implementation of the 2003 law and restoring the capitated fee vs fee for service funding balance to its original intended parity level.
The intention of both the 1997 and 2003 law was that the differences between fee for service and capitated fee beneficiaries would reach parity over time and that has mostly been achieved, given that it can never literally be achieved without a major reform of Medicare because the Part C capitated fee in one year is based on the fee for service spending the previous year.
Enrollment in public Part C health plans, including Medicare Advantage plans, grew from about 1% of total Medicare enrollment in 1997 when the law was passed (the 1% representing people on pre-law demonstration programs) to about 37% in 2019. Of course the absolute number of beneficiaries on Part C has increased even more dramatically on a percentage basis because of the large increase of people on Original Medicare since 1997. Almost all Medicare beneficiaries have access to at least two public Medicare Part C plans; most have access to three or more.