Nearly one in three patients receiving NHS hospital treatment is privately insured and could have the cost paid for by their insurer. Some private schemes provide cash payments to patients who opt for NHS treatment, to deter use of private facilities. A report, by private health analysts Laing and Buisson, in November 2012, estimated that more than 250,000 operations were performed on patients with private medical insurance each year at a cost of £359 million. In addition, £609 million was spent on emergency medical or surgical treatment. Private medical insurance does not normally cover emergency treatment but subsequent recovery could be paid for if the patient were moved into a private patient unit.[44]
The United States health care system relies heavily on private health insurance, which is the primary source of coverage for most Americans. As of 2012 about 61% of Americans had private health insurance according to the Centers for Disease Control and Prevention.[56] The Agency for Healthcare Research and Quality (AHRQ) found that in 2011, private insurance was billed for 12.2 million U.S. inpatient hospital stays and incurred approximately $112.5 billion in aggregate inpatient hospital costs (29% of the total national aggregate costs).[57] Public programs provide the primary source of coverage for most senior citizens and for low-income children and families who meet certain eligibility requirements. The primary public programs are Medicare, a federal social insurance program for seniors and certain disabled individuals; and Medicaid, funded jointly by the federal government and states but administered at the state level, which covers certain very low income children and their families. Together, Medicare and Medicaid accounted for approximately 63 percent of the national inpatient hospital costs in 2011.[57] SCHIP is a federal-state partnership that serves certain children and families who do not qualify for Medicaid but who cannot afford private coverage. Other public programs include military health benefits provided through TRICARE and the Veterans Health Administration and benefits provided through the Indian Health Service. Some states have additional programs for low-income individuals.[58]
The terms "open panel" and "closed panel" are sometimes used to describe which health care providers in a community have the opportunity to participate in a plan. In a "closed panel" HMO, the network providers are either HMO employees (staff model) or members of large group practices with which the HMO has a contract. In an "open panel" plan the HMO or PPO contracts with independent practitioners, opening participation in the network to any provider in the community that meets the plan's credential requirements and is willing to accept the terms of the plan's contract.
Hospital and medical expense policies were introduced during the first half of the 20th century. During the 1920s, individual hospitals began offering services to individuals on a pre-paid basis, eventually leading to the development of Blue Cross organizations.[65] The predecessors of today's Health Maintenance Organizations (HMOs) originated beginning in 1929, through the 1930s and on during World War II.[67][68]

Australian health funds can be either 'for profit' including Bupa and nib; 'mutual' including Australian Unity; or 'non-profit' including GMHBA, HCF and the HBF Health Fund (HBF). Some, such as Police Health, have membership restricted to particular groups, but the majority have open membership. Membership to most health funds is now also available through comparison websites like moneytime, Compare the Market, iSelect Ltd., Choosi, ComparingExpert and YouCompare. These comparison sites operate on a commission-basis by agreement with their participating health funds. The Private Health Insurance Ombudsman also operates a free website which allows consumers to search for and compare private health insurers' products, which includes information on price and level of cover.[9]
As the population covered by Medicare grows, its costs are projected to rise from slightly over 3 percent of GDP to over 6 percent, contributing substantially to the federal budget deficit.[47] In 2011, Medicare was the primary payer for an estimated 15.3 million inpatient stays, representing 47.2 percent ($182.7 billion) of total aggregate inpatient hospital costs in the United States.[12] The Affordable Care Act took some steps to reduce Medicare spending, and various other proposals are circulating to reduce it further.
In addition to medical expense insurance, "health insurance" may also refer to insurance covering disability or long-term nursing or custodial care needs. Different health insurance provides different levels of financial protection and the scope of coverage can vary widely, with more than 40% of insured individuals reporting that their plans do not adequately meet their needs as of 2007.[2]