Plain version: Medicare Advantage plans are managed care offered by private companies. The plan types differ mainly in how strictly they tie members to a network and who may join.
HMO and PPO:
HMO: members generally must use the network, except for emergency care, out-of-area urgent care and temporary out-of-area dialysis. They usually choose a primary care doctor and need referrals.
PPO: members pay less in the network but can generally go out of network for covered services at a higher cost. No primary care doctor or referral is required.
Private Fee-for-Service (PFFS): the plan decides how much it pays providers and what members pay. Members may see any Medicare-approved provider who accepts the plan's terms and agrees to treat them, and a provider can make that choice at every visit. No primary care doctor or referral is needed, and Part D drug coverage is optional for the plan.
Special Needs Plans (SNPs): an SNP is a coordinated care plan, an HMO or PPO type, that enrolls only special needs individuals: people with Medicaid (Medi-Cal in California), people who are institutionalized or the equivalent, or people with a severe or disabling chronic condition. Every SNP must provide Part D drug coverage. A Chronic Condition SNP (C-SNP) focuses on one or more such conditions, and the federal list includes chronic kidney disease requiring dialysis/end-stage renal disease (ESRD).
Dual Eligible SNP (D-SNP):
Purpose: to coordinate Medicare and Medi-Cal services for people eligible for both. A D-SNP must hold a contract with the state Medicaid agency, and in California integrated D-SNPs are called Medi-Medi Plans. It works with Medi-Cal rather than replacing it.
Eligibility: the CDI outline says the eligible group includes people with a Medi-Cal Share of Cost. For Medi-Medi Plans, the Department of Health Care Services (DHCS) lists Medicare Part A and Part B, Medi-Cal and age 21 or older. Membership is limited to people in the affiliated Medi-Cal managed care plan, and availability depends on the county.
Stand-alone drug plans: the CDI outline says enrolling in a stand-alone prescription drug plan (PDP) automatically terminates enrollment in a Medicare Advantage plan. Under current rules this is true for an HMO or PPO even if the plan has no drug coverage, but there are exceptions: a separate PDP can be added to a PFFS plan without Part D, a Medical Savings Account plan or a Medicare Cost Plan.
What every plan must do and may add:
Must cover all services covered by Part A and Part B in its service area and follow Medicare's coverage rules; it may cover more or charge less.
Has a yearly limit on what a member pays for covered services; after reaching it, the member pays nothing for covered services for the rest of the year. Original Medicare has no such limit, so a plan can reduce a senior's out-of-pocket exposure.
May add benefits Original Medicare does not cover, such as some dental, vision and hearing services.
May offer optional supplemental benefits: the enrollee chooses and pays for them, and they must be offered to all enrollees regardless of health status. The outline also mentions "value added" services.