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. The predecessors of today's Health Maintenance Organizations (HMOs) originated beginning in 1929, through the 1930s and on during World War II.
A recent study by PricewaterhouseCoopers examining the drivers of rising health care costs in the U.S. pointed to increased utilization created by increased consumer demand, new treatments, and more intensive diagnostic testing, as the most significant. However, Wendell Potter, a long-time PR representative for the health insurance industry, has noted that the group which sponsored this study, AHIP, is a front-group funded by various insurance companies. People in developed countries are living longer. The population of those countries is aging, and a larger group of senior citizens requires more intensive medical care than a young, healthier population. Advances in medicine and medical technology can also increase the cost of medical treatment. Lifestyle-related factors can increase utilization and therefore insurance prices, such as: increases in obesity caused by insufficient exercise and unhealthy food choices; excessive alcohol use, smoking, and use of street drugs. Other factors noted by the PWC study included the movement to broader-access plans, higher-priced technologies, and cost-shifting from Medicaid and the uninsured to private payers.
Before the development of medical expense insurance, patients were expected to pay health care costs out of their own pockets, under what is known as the fee-for-service business model. During the middle-to-late 20th century, traditional disability insurance evolved into modern health insurance programs. One major obstacle to this development was that early forms of comprehensive health insurance were enjoined by courts for violating the traditional ban on corporate practice of the professions by for-profit corporations. State legislatures had to intervene and expressly legalize health insurance as an exception to that traditional rule. Today, most comprehensive private health insurance programs cover the cost of routine, preventive, and emergency health care procedures, and most prescription drugs (but this is not always the case).
Health, as defined by the World Health Organization (WHO), is "a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity." This definition has been subject to controversy, as it may have limited value for implementation. Health may be defined as the ability to adapt and manage physical, mental and social challenges throughout life.