The second half of the 20th century witnessed spectacular advances in health care. Innovations such as magnetic resonance imaging, genetically engineered growth factors, and highly effective drugs for the treatment of depression, gastroesophageal reflux, high blood cholesterol, and HIV disease greatly improved the detection and treatment of both rare and common diseases. The advances greatly improved the outcomes of complex procedures such as organ transplantation, coronary artery bypass surgery, and high-dose chemotherapy (bone marrow transplantation) for acute myeloid leukemia and multiple myeloma. As the 21st century opens, technological progress in medicine is continuing and may be accelerating. It is a source of hope for the prevention, effective treatment, and cure of disease.
Technological innovation is also the major source of increases in real per capita medical spending in the United States. If medical advances continue to be adopted as rapidly as they have been, they will pose knotty economic, political, and ethical challenges for health care policy at a time when spending on health care in the United States has once again begun to surge after a mid-1990s pause and the number of Americans without health insurance has once again begun growing.