"The potential impact of the growing prevalence of pain on the health care system is substantial. Although not all people with chronic low back pain are treated within the health care system, many are, and 'back problems' are one of the nation’s 15 most expensive medical conditions. In 1987, some 3,400 Americans with back problems were treated for every 100,000 people; by 2000, that number had grown to 5,092 per 100,000. At the same time, health care spending for these treatments had grown from $7.9 billion to $17.5 billion. Thorpe and colleagues (2004) estimate that low back pain alone contributed almost 3 percent to the total national increase in health care spending from 1987 to 2000. While about a quarter of the $9.5 billion increase could be attributable to increased population size, and close to a quarter was attributable to increased costs of treatment, more than half of the total (53 percent) was attributable to a rise in the prevalence of back problems."

Source

Institute of Medicine, "Relieving Pain in America: A Blueprint for Transforming Prevention, Care, Education, and Research" (Washington, DC: National Academy of Sciences, 2011), p. 64.
http://www.nap.edu/openbook.p…