What a Medicare HMO Is and How It Works

Medicare HMO basics

A Medicare HMO (Health Maintenance Organization) is a type of Medicare Advantage plan that bundles your hospital, doctor, and prescription drug coverage into one plan run by a private insurance company. Unlike Original Medicare, where you can see any doctor who accepts Medicare, an HMO requires you to choose a primary care doctor and get referrals to see specialists. You must use doctors and hospitals in the plan's network, except in emergencies.

The main trade-off is lower out-of-pocket costs — HMOs typically have lower premiums and copays than other Medicare plans — but less flexibility about which doctors you can see. If you go outside the network without an emergency, the HMO will not pay, and you will owe the full bill.

Key Takeaways

A Medicare HMO requires you to pick a primary care doctor and stay within the plan's network of doctors and hospitals, except in emergencies.
HMOs usually cost less per month and have lower copays than Original Medicare or PPO plans, but offer less choice of providers.
You need a referral from your primary care doctor to see a specialist, which can add time to getting care.
If you travel frequently or have doctors you want to keep, check whether they are in the HMO's network before you enroll.

How the network requirement works

Every Medicare HMO has a list of doctors, hospitals, and other providers it contracts with — this is called the network. When you enroll, you choose a primary care doctor from that list. This doctor becomes your main point of contact for all your medical care and coordinates any specialist visits you need.

If you see a doctor outside the network without an emergency, the plan does not pay. You will receive a bill for the full cost. The only exception is true emergencies — if you are having a heart attack or stroke, you can go to any emergency room, and the HMO will cover it. Urgent care that cannot wait for a referral is usually covered too, but call the plan first if you can.

Networks vary widely by plan and by region. A plan available in one county may have very different doctors than the same plan name in a neighboring county. Before you enroll, ask the plan for a current provider directory and check whether your current doctors are listed.

Referrals and how they affect your care

To see a specialist — a cardiologist, rheumatologist, or any doctor outside your primary care doctor's office — you need a referral. Your primary care doctor submits this referral to the HMO, and the plan approves or denies it. This step can add a week or more to getting an appointment, especially if your primary care doctor is slow to submit the referral or if the HMO needs more information.

Some referrals are routine and approved quickly. Others — particularly for expensive procedures or newer treatments — may require the HMO to review medical records first. If the HMO denies a referral, you have the right to appeal, but that takes additional time. Ask your primary care doctor how long referrals typically take in your plan so you know what to expect.

Costs: premiums, copays, and deductibles

Medicare HMOs usually have lower monthly premiums than Original Medicare combined with a Medigap policy, and copays are often lower too. You might pay $10 to $30 per doctor visit, $50 to $100 for an emergency room visit, and $5 to $50 per prescription, depending on the plan. Many HMOs also include prescription drug coverage built in, so you do not need a separate Part D plan.

However, HMOs have an annual out-of-pocket maximum — a cap on how much you pay in copays and coinsurance in a year. Once you hit that limit, the plan pays 100 percent of covered services for the rest of the year. This maximum varies by plan but is set by Medicare each year. Original Medicare has no out-of-pocket maximum, which is why some people with high medical costs prefer it.

Some HMOs offer extra benefits that Original Medicare does not cover, such as dental, vision, or hearing aids. These vary widely by plan and region, so compare what is included before you enroll.

HMO versus Original Medicare and PPO plans

Original Medicare (Part A and Part B) lets you see any doctor who accepts Medicare without a referral. You pay a deductible and coinsurance for each service, and there is no out-of-pocket maximum. Many people add a Medigap policy to cover the gaps, which raises the total monthly cost but gives more predictable expenses.

A Medicare PPO (Preferred Provider Organization) is less restrictive than an HMO. You can see any doctor without a referral, but you pay less if you use in-network providers. You can go out of network and still get some coverage, though you will pay more. PPOs usually cost more per month than HMOs but offer more flexibility.

The choice depends on your situation. If you have doctors you want to keep and do not mind higher costs, Original Medicare or a PPO may suit you better. If you want predictable, lower monthly costs and do not mind using a primary care doctor and network, an HMO is often the cheapest option.

What to check before you enroll in an HMO

Before you sign up, verify that your current doctors are in the plan's network. Call the plan or use its online provider search tool and search by name. Ask whether your doctors are accepting new patients, because being in the network does not mean they are taking new HMO members.

If you take prescription medications, check the plan's formulary — the list of drugs it covers. Not all drugs are covered, and some require prior approval from the HMO before the pharmacy will fill them. If a drug you need is not on the formulary, ask whether the plan will make an exception or whether you will have to switch medications.

Ask about the referral process. How long does it usually take? Can your primary care doctor submit referrals electronically, or does it require a phone call? If you see specialists regularly, a slow referral process can be frustrating. Also ask about the appeal process if the HMO denies a referral you think you need.

When an HMO might not be the right choice

If you travel frequently, especially outside your plan's service area, an HMO can be risky. Coverage is usually limited to your home region, and you will pay out of pocket for care received elsewhere unless it is an emergency. If you spend winters in another state or travel for work, a PPO or Original Medicare may be safer.

If you have a complex medical condition and see multiple specialists, the referral requirement can slow your care. Some people find it frustrating to need permission from their primary care doctor every time they need specialist care. If you value independence in choosing your doctors, an HMO may feel restrictive.

If you have a doctor you are deeply committed to and that doctor is not in the HMO's network, you cannot use that plan. Switching doctors is possible but not always straightforward, especially if you have a long-standing relationship or a complex condition.

Frequently Asked Questions

Can I switch out of a Medicare HMO if I do not like it?

Yes. You can switch during the Annual Enrollment Period (October 15 to December 7 each year), and your new coverage starts January 1. You can also switch during the Medicare Advantage Open Enrollment Period (January 1 to March 31) if you are already in a Medicare Advantage plan. Outside these windows, you cannot switch unless you have a may have access to life event, such as moving out of the plan's service area.

What happens if my doctor leaves the HMO network?

If your primary care doctor leaves the network mid-year, the HMO must notify you and give you time to choose a new primary care doctor. You can usually continue seeing that doctor for a short transition period while you find a new one. If a specialist you are seeing leaves the network, ask the HMO whether you can finish your current course of treatment with that doctor.

Do I still have Medicare if I enroll in an HMO?

Yes. A Medicare HMO is a way to receive your Medicare benefits, not a replacement for Medicare. You keep your Medicare card and your Part A and Part B coverage. The HMO is the company that administers your benefits and coordinates your care.

What if I need care while I am traveling?

Emergency care is covered anywhere in the United States. For urgent care that is not life-threatening, call the HMO first to ask whether the urgent care center or clinic you plan to visit is in-network or whether the plan will cover it. Routine care outside your service area is typically not covered unless you arrange it in advance with the HMO.

Can an HMO refuse to cover a treatment my doctor recommends?

Yes. If your doctor recommends a treatment and the HMO denies the referral or refuses to cover it, you have the right to appeal. You can ask your doctor to submit additional medical information to support the request, or you can file a formal appeal with the HMO. If the appeal is denied, you can request an independent review by an outside organization.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.