June 21, 2011 -- Specific drugs used to treat inflammatory diseases like rheumatoid arthritis (RA) and psoriasis may also help protect patients with these conditions from developing type 2 diabetes, a study shows.
Use of TNF-inhibitor biologic agents such as Enbrel, Humira, and Remicade, and hydroxychloroquine (Plaquenil, Quineprox) was associated with a lower diabetes risk among patients with the inflammatory conditions than use of other disease-modifying antirheumatic drugs (DMARDs) in the study from Harvard Medical School and Brigham and Women's Hospital.
Reducing Insulin Resistance
The early findings suggest certain DMARDs lower insulin resistance and help prevent diabetes in patients with these conditions, study researcher Daniel H. Solomon, MD, MPH, tells WebMD.
The study appears in the June 22/29 issue of the Journal of the American Medical Association.
"We are not at the point where we can make clinical leaps and say that these are the drugs to choose for high-risk patients," Solomon says. "But if future studies support the conclusion that these drugs do decrease insulin resistance and diabetes risk, one could imagine a day when we make treatment decisions based on these comorbidities."
Analyzing Diabetes Risk
Solomon and colleagues analyzed the health records of close to 14,000 patients with rheumatoid arthritis or psoriasis enrolled in two large private health insurance programs -- one in Canada and one in the U.S.
The patients were followed from the time they started one of four categories of commonly prescribed DMARDs: biologic TNF inhibitors, methotrexate, hydroxychloroquine, and other non-biologic agents.
During the follow-up period, 267 new cases of diabetes were diagnosed among the patients.
After taking into account known diabetes risk factors, patients treated with hydroxychloroquine were 46% less likely to develop diabetes and those treated with a TNF inhibitor had a 38% lower risk than patients taking other non-biologic agents.
Methotrexate use was associated with a non-significant reduction in diabetes risk.
Matching Patients With the Right Drugs
Solomon and colleagues are currently conducting a study, sponsored by the National Institutes of Health, that's designed to examine whether hydroxychloroquine improves glucose and insulin profiles in rheumatoid arthritis patients.
He says if this study and others prove positive, routine assessment of insulin resistance may become common in the management of patients with inflammatory diseases.
"We currently have about a dozen drugs that we give patients with rheumatoid arthritis, but we don't really have a clear way of determining which drug is best for which patient," he says. "Understanding how these drugs affect comorbidities like diabetes could help us make more informed treatment choices."
Rheumatologist Tim Bongartz, MD, agrees, but he says we are not there yet.
Bongartz is an assistant professor of medicine at the Mayo Clinic in Rochester, Minn.
"Basic research now tells us that inflammation plays an important role in the development of type 2 diabetes, as well as type 1 diabetes," he tells WebMD. "If randomized trials are promising, diabetes risk may prove to be an important consideration when choosing a treatment strategy for patients with systemic inflammatory disease."