What is an HMO plan?

The most popular type of Medicare Advantage plan is the one sponsored by a Health Maintenance Organization (HMO).

Almost two-thirds of those enrolled in Medicare Advantage were in an HMO plan in 2019.

An HMO generally requires a member to select a primary physician who will coordinate care. The member must see providers in the network for routine (non-emergency) medical care. In most HMO plans, that physician must make a referral in order for a member to see a specialist. Other than for true emergency situations, an HMO may not pay for care outside the network.  

Besides referral requirements, HMO plans can also require prior authorization. In the case of a procedure or test, the plan will either approve or deny the request. For services such as outpatient therapy or home healthcare, the plan will likely approve a certain number of visits. If the plan does not approve the order, the beneficiary will not get the service or treatment or will pay privately for it.