The most common reasons for medical evacuation of military personnel from war zones in Iraq and Afghanistan in recent years have been fractures, tendonitis and other musculoskeletal and connective tissue disorders, not combat injuries, according to results of a Johns Hopkins study published January 22 in The Lancet.

"Most people think that in a war, getting shot is the leading cause of medical evacuation, but it almost never is," says study leader Steven P. Cohen, M.D., associate professor of anesthesiology at the Johns Hopkins University School of Medicine and a colonel in the U.S. Army Reserves. "As in the past, disease and non-battle-related injuries continue to be the major sources of service-member attrition and that's not likely to change. It's likely to get worse."

The Johns Hopkins researchers looked at the records of more than 34,000 members of the military who were sent to the military's medical center in Landstuhl, Germany from 2004 through 2007. The top three grounds for medical evacuation were musculoskeletal or connective tissue disorders (24 percent), combat injuries (14 percent) and neurological disorders (10 percent). There wasn't much change in those percentages over the course of the four years analyzed, but the percentage of personnel leaving with psychiatric diagnoses continued to rise each year, an increase seen despite the introduction of mental health teams devoted to treating combat stress on site.

Cohen and his colleagues believe these increases may partly be the result of the cumulative psychological effects of repeated deployments and the increasing manpower burden borne by reserve and National Guard units. Those factors are unlikely to change as the wars continue, they say.

Most of those evacuated from Iraq and Afghanistan for medical and psychiatric reasons don't return, the data show. In 2007, only one in five military personnel returned to duty in the country from which they were evacuated. Previous studies have shown that the farther away from the deployment area soldiers are treated, the less likely they are to return to duty in that war zone. A previous study by Cohen showed that when military personnel with back pain were taken to a pain clinic in Iraq, all patients returned to their units. When they were sent to pain clinics in Germany or in Washington, fewer than 2 percent did.

"The planes go from East to West, not from West to East," he says.

The new study also found that patients who were senior officers were more likely to return to duty after evacuation, likely because they have chosen careers in the military, Cohen says. Service members of all ranks with combat injuries, psychiatric disorders, musculoskeletal and connective tissue disorders, and spinal pain were less likely to return.

One reason for so many non-battle-related injuries, Cohen says, is the changing nature of warfare. "We have a lot of people in Afghanistan and Iraq and their main job isn't fighting," he said.

Cohen says it is important for the military to understand the reasons why its personnel are being evacuated and to work to better prevent injuries and illness. Wherever possible, he says, medical staff in Iraq and Afghanistan should be trained to aggressively treat problems early before they snowball.

"For some of the musculoskeletal problems, you may not be able to prevent them," he says. "Most people doing their jobs in heavy gear, like Kevlar, are going to get overuse injuries like knee pain, hip pain and bursitis. But you need to recognize and treat problems before they become severe."

Other Johns Hopkins researchers involved in the study include Charlie Brown, M.D., Connie Kurihara, R.N., and Anthony Plunkett, M.D.

The research was funded by the John P. Murtha Neuroscience and Pain Institute in Johnstown, Penn.; the U.S. Army; and the Army Regional Anesthesia and Pain Medicine Initiative.