FRIDAY, Sept. 14 (HealthDay News) -- Americans spend as much as $635 billion each year on the direct and indirect costs associated with chronic pain, according to a new study.

That's more than the annual costs associated with cancer, heart disease and diabetes, said study authors Darrell Gaskin and Patrick Richard, health economists at Johns Hopkins University. They based their estimate on health care costs and lost worker productivity associated with chronic pain.

The researches analyzed the 2008 Medical Expenditure Panel Survey to measure the incremental health care costs for people affected by chronic pain -- including pain that interferes with work, joint pain, arthritis and disabilities -- and compared them to costs for people without chronic pain. The study involved more than 20,200 U.S. adults.

The costs of certain conditions were calculated for a variety of payers of health care services, the researchers noted.

The study, published in the Journal of Pain, found average health care costs for adults were $4,475. People suffering from moderate pain paid $4,516 more in health care costs than those without pain, the researchers said. Patients with severe pain spent $3,210 more than people with only moderate pain. Costs were also $4,048 higher for those with joint pain, $5,838 higher for people with arthritis and $9,680 more for those with functional disabilities.

When prevalence of pain conditions was assessed, moderate pain accounted for 10 percent, severe pain accounted for 11 percent and disability represented 12 percent. Estimates for joint pain and arthritis were higher. They accounted for 33 percent and 25 percent of prevalence estimates, respectively.

The researchers noted that adults affected by chronic pain missed more workdays than people without pain. This affected their annual hours worked and hourly wages. The study concluded the total cost associated with pain in the United States was at least $560 billion and possibly as high as $635 billion, according to a release from the American Pain Society.

Broken down, the total incremental costs of health care resulting from chronic pain ranged from $261 billion to $300 billion. And the costs associated with lost productivity ranged from $299 billion to $334 billion. Although the per-person cost of pain is less than the cost of other diseases, the researchers said the total cost of chronic pain is higher. They said the costs associated with chronic pain would be even greater if they took into account nursing home residents, military personnel, prisoners, children and caregivers.

More information

The U.S. National Institute of Neurological Disorders and Stroke provides more information on chronic pain.

THURSDAY, Sept. 13 (HealthDay News) -- Care provided by medical specialists is the main reason spending on treatment for back and neck problems in the United States has nearly doubled since the late 1990s, according to a new study.

Researchers analyzed data on how much Americans spent on ambulatory (non-hospital) care for back and neck problems from 1999 to 2008. The study was published Sept. 1 in the journal Spine.

In 2008, about 6 percent of adults made an ambulatory care visit for diagnosis of a back or neck condition, a total approaching 14 million visits. The researchers found that the percentage of patients who made ambulatory spinal care visits during the study period remained "remarkably stable," according to a journal news release

Adjusted for inflation, annual medical spending for spinal care per patient increased by 95 percent from 1999 to 2008, from $487 to $950 in 2008 dollars. Most of the spending increase was for treatment by medical specialists. There was little or no change in spending for spinal care provided by primary care and family doctors, internists or general practitioners.

Spending for care provided by chiropractors also remained stable, the researchers found. Spending for care by physical therapists was the most costly service throughout the study period, but appeared to decrease over time.

"Recent increasing costs associated with providing medical care for back and neck conditions -- particularly subspecialty care -- are contributing to the growing economic burden of managing these conditions," wrote study author Matthew Davis and colleagues at the Dartmouth Institute in Lebanon, N.H.

They noted that back pain is the second most common reason for medical visits, after upper respiratory infections.

"Estimates of the total expenditures on care vary, but the general consensus is that approximately $90 billion is spent on the diagnosis and management of low-back pain, and an additional $10 billion to $20 billion is attributed to economic losses in productivity each year," the researchers wrote.

More information

The North American Spine Society offers back-pain prevention tips  .