KFF Publishes Medicare 101 Primer Covering 68 Million Enrollees

KFF, a nonprofit health policy research organization formerly known as the Kaiser Family Foundation, published a Health Policy 101 chapter on Medicare on October 1, 2026, laying out how the program works for its more than 68 million beneficiaries. According to KFF, Medicare is the federal health insurance program established in 1965 for people age 65 and older, later expanded to cover people under 65 with long-term disabilities. The chapter walks through eligibility rules, coverage categories, program spending, the expanding role of private insurance plans, and the financing pressures created by rising health care costs and an aging population. For Medicare Plan Path readers, this kind of foundational explainer is a useful checkpoint, especially for anyone approaching age 65 or helping a family member sort through enrollment choices for the first time.

The source document is an educational reference rather than a policy announcement, so there is no new rule, deadline, or benefit change to act on immediately. Its value is in how clearly it frames the structure beneficiaries are already navigating: Original Medicare (Parts A and B run directly by the federal government), Medicare Advantage (Part C, private plans that replace Original Medicare), and Part D (standalone prescription drug coverage). Understanding that structure is the first step toward comparing plans accurately during enrollment windows.

Private Plans Now Cover a Majority of Beneficiaries

One of the explainer's central themes is the increased role of private plans in delivering Medicare benefits. Medicare Advantage plans are private insurance plans, approved by the Centers for Medicare & Medicaid Services (CMS), that bundle Part A, Part B, and usually Part D coverage into a single plan, often with additional benefits like dental or vision. Enrollment in these plans has grown steadily over the past decade, to the point where private plans now cover more than half of all Medicare beneficiaries nationwide, a shift KFF's chapter documents as part of the program's long-term evolution.

This growth matters for plan comparison because Medicare Advantage and Original Medicare work differently in practice. Medicare Advantage plans typically use provider networks, require referrals for specialists in some cases, and cap annual out-of-pocket spending, something Original Medicare does not do on its own. Original Medicare offers broader provider access nationwide but usually requires a separate Medigap (Medicare Supplement) policy and a standalone Part D plan to limit cost exposure. Neither structure is universally better; the right fit depends on a beneficiary's providers, prescriptions, travel habits, and budget for premiums versus out-of-pocket costs.

Key Takeaway

KFF's explainer is a reference document, not a benefit change, but it is a reminder that Medicare's mix of public and private coverage keeps shifting. Beneficiaries should recheck their plan choice every year during Medicare Open Enrollment, which runs October 15 to December 7, 2026, rather than assuming last year's plan is still the best fit.

Financing Pressures Could Shape Future Coverage

The KFF chapter also addresses financing challenges tied to rising health care costs and an aging population, factors that influence how much beneficiaries pay and what plans can offer. Medicare Part A is funded primarily through a trust fund supported by payroll taxes, and its long-term solvency has been a recurring subject of congressional and actuarial review. As the beneficiary population grows and per-person health spending rises, policymakers face ongoing decisions about premiums, cost-sharing, and how private plans are paid relative to Original Medicare. KFF's explainer does not predict specific legislative outcomes, and none are confirmed as of this writing; it simply frames financing as a structural issue worth understanding alongside eligibility and coverage basics.

For readers, the practical implication is that plan benefits, premiums, and cost-sharing can change from year to year as CMS and insurers adjust to these pressures. That is a core reason the annual Open Enrollment Period exists: plans update their formularies, provider networks, and cost structures annually, and a plan that worked well in 2025 may look different in 2026.

What Medicare Beneficiaries Should Do Next

Readers can use KFF's framework as a prompt to revisit their own coverage rather than as a reason to make changes immediately. A few concrete steps apply regardless of where someone is in their Medicare journey:

If approaching age 65: Confirm your Initial Enrollment Period, a seven-month window centered on your 65th birthday month, and decide whether Original Medicare plus Medigap and Part D, or a Medicare Advantage plan, better matches your providers and prescriptions.

If already enrolled: Use the current Open Enrollment Period, October 15 through December 7, 2026, to compare your existing Medicare Advantage or Part D plan against alternatives using the Medicare Plan Finder tool at Medicare.gov, since formularies and provider networks can change annually.

If unsure which structure fits: Consider speaking with a licensed Medicare agent or using a State Health Insurance Assistance Program (SHIP) counselor, both of which can walk through plan options without a sales obligation. This article is educational and does not substitute for personalized advice based on your specific health needs and finances.

KFF's full Medicare 101 chapter is available at kff.org for readers who want the complete breakdown of eligibility, spending, and financing data behind these basics.