It is this inclusion of services intended to maintain a member's health that gave the HMO its name. Some services, such as outpatient mental health care, are often provided on a limited basis, and more costly forms of care, diagnosis, or treatment may not be covered. Experimental treatments and elective services that are not medically necessary (such as elective plastic surgery) are almost never covered.Other methods for managing care are case management, in which patients with catastrophic cases are identified, or disease management, in which patients with certain chronic diseases like diabetes, asthma, or some forms of cancer are identified. In either case, the HMO takes a greater level of involvement in the patient's care, assigning a case manager to the patient or a group of patients to ensure that no two providers provide overlapping care, and to ensure that the patient is receiving appropriate treatment, so that the condition does not worsen beyond what can be helped.HMOs often shift some financial risk to providers through a system called capitation, where certain providers (usually PCPs) receive a fixed payment per member per month and in return provide certain services for free.

Under this arrangement, the provider does not have the incentive to provide unnecessary care, as they will not receive any additional payment for the care. However, as a side effect of the contractually structured payment plan given to the provider, there is an incentive to provide only the minimal contractually obligated healthcare, thereby maximizing profits. To counterbalance this trend some plans offer a bonus to providers whose care meets a predetermined level of quality.Some criticswho? regard HMOs as monopolies that distort the market for health care. HistoryThe earliest form of HMOs can be seen in a number of prepaid health plans. In 1910, the Western Clinic in Tacoma, Washington offered lumber mill owners and their employees certain medical services from its providers for a premium of $0.50 per member per month. This is considered by some to be the first example of an HMO. However, Ross-Loos Medical Group, established in 1929, is considered to be the first HMO in the United States; it was headquartered in Los Angeles and initially provided services for Los Angeles Department of Water and Power (DWP) and Los Angeles County employees.

Approximately 500 DWP employees enrolled at a cost of $1.50 each per month. Within a year, the Los Angeles Fire Department signed up, then the Los Angeles Police Department, then the Southern California Telephone Company, (now at&t) and more. By 1951, enrollment stood at 35,000 and included teachers, county and city employees. In 1982 through the merger of the Insurance Company of North America (INA) founded in 1792 and Connecticut General (CG) founded in 1865 came together to become CIGNA. Ross-Loos Medical Group, became now known as CIGNA HealthCare. Also in 1929 Dr. Michael Shadid created a health plan in Elk City, Oklahoma in which farmers bought shares for $50 to raise the money to build a hospital. The medical community did not like this arrangement and threatened to suspend Shadid's licence. The Farmer's Union took control of the hospital and the health plan in 1934. Also in 1929, Baylor Hospital provided approximately 1,500 teachers with prepaid care. This was the origin of Blue Cross.

Around 1939, state medical societies created Blue Shield plans to cover physician services, as Blue Cross covered only hospital services. These prepaid plans burgeoned during the Great Depression as a method for providers to ensure constant and steady revenue.In 1970, the number of HMOs declined to less than 40.

Health Maintenance Organization (HMO)

A health maintenance organization (HMO) is a type of managed care organization (MCO) that provides a form of health care coverage in the United States that is fulfilled through hospitals, doctors, and other providers with which the HMO has a contract. The Health Maintenance Organization Act of 1973 required employers with 25 or more employees to offer federally certified HMO options. Unlike traditional indemnity insurance, care provided in an HMO generally follows a set of care guidelines and is provided through the HMO's network of providers. Under this model, providers contract with an HMO to receive more patients and in return usually agree to provide services at a discount. This arrangement allows the HMO to charge a lower monthly premium, which is an advantage over indemnity insurance, provided that its members are willing to abide by the additional restrictions. Operation The neutrality of this article is disputed.Please see the discussion on the talk page.(December 2007)Please do not remove this message until the dispute is resolved.

In addition to using their contracts with providers for services at a lower price, HMOs hope to gain an advantage over traditional insurance plans by managing their patients' health care and reducing unnecessary services. To achieve this, most HMOs require members to select a primary care physician (PCP), a doctor who acts as a "gatekeeper" to medical services. PCPs are usually internists, pediatricians, family doctors, or general practitioners. In a typical HMO, most medical needs must first go through the PCP, who authorizes referrals to specialists or other doctors if deemed necessary. Emergency medical care does not require prior authorization from a PCP, and many plans allow women to select an OB/GYN in addition to a PCP, whom they may see without a referral. In some cases, a chronically ill patient may be allowed to select a specialist in the field of their illness as a PCP."Open access" HMOs do not use primary care physicians as gatekeepers - there is no requirement to obtain a referral before seeing a specialist.

The beneficiary cost sharing (e.g., co-payment or coinsurance) may be higher for specialist care, however.As with most health insurance plans in the United States, HMOs also manage care through utilization review. The amount of utilization is usually expressed as a number of visits or services or a dollar amount per member per month (PMPM). Utilization review is intended to identify providers providing an unusually high amount of services, in which case some services may not be medically necessary, or an unusually low amount of services, in which case patients may not be receiving appropriate care and are in danger of worsening a condition. HMOs often provide preventive care for a lower copayment or for free, in order to keep members from developing a preventable condition that would require a great deal of medical services. When HMOs were coming into existence, indemnity plans often did not cover preventive services, such as immunizations, well-baby checkups, mammograms, or physicals.