Depression risk factor for mortality in rheumatoid arthritis; men most at risk

Rheumatoid arthritis is a chronic disease that causes pain, stiffness, swelling, limitation of motion and loss of function of multiple joints. Though joints are the principal areas affected by RA, inflammation can develop in other organs as well. An estimated 1.3 million Americans have RA, and the disease typically affects women twice as often as men.

Researchers used data collected from annual telephone surveys of 530 participants with RA who live in northern California to assess symptoms of depression and the potential impact of depression in this population. To qualify as depressed, participants must score greater than five on the Geriatric Depression Scale, a standardized measurement tool.

To be eligible, participants had to undergo an interview in either 2002 or 2003 with at least one follow-up interview. They were then followed until 2009. Participants' mean age was 60 with a mean disease duration of 19 years, and 84 percent were female. During the study, 63 participants died. Higher depression scores were associated with mortality in the study, said Patricia Katz, PhD, investigator in the study and professor of medicine and health policy at University of California, San Francisco.

"People with rheumatoid arthritis who were depressed were more likely to die than those with RA who were not depressed. We found that seemed to be particularly true for the men. The risk of death for depressed men was twice that for depressed women," says Dr. Katz.

Overall, men in this study had a higher mortality risk than women, after controlling for other variables. This was true for both depressed and non-depressed individuals; a baseline history of depression by the Geriatric Depression Scale resulted in approximately twice the mortality for both genders. When the increased risk associated with gender was combined with the risk associated with depression, men in the study whose scores indicated depression were five times as likely to die as women with RA whose scores indicated they were not depressed.

Men and women with increases in depressive symptoms, who may not have scored high enough on the Geriatric Depression Scale to be considered depressed, still had a higher mortality risk, says Dr. Katz. "An increase in the depressive symptom score, even if they didn't cross over that critical line to overt depression, was still associated with a higher level of mortality."

The study's findings suggest that depression and depressive symptoms are a significant risk factor for mortality in RA, although it is not necessarily a part of the disease process, says Dr. Katz.

"Patients need to be made aware that depression is something to pay attention to in RA, and they need to tell their physician about it. Rheumatologists and other health care providers need to be aware of the problem of depression in the clinical setting," Dr. Katz says.

Funding for this study was provided by the National Institute for Arthritis, Musculoskeletal, and Skin Diseases of the National Institutes of Health.