Preliminary research has suggested that use of the anti-malarial drug hydroxychloroquine may help reduce the risk of patients with rheumatoid arthritis developing diabetes.

Type 2 diabetes mellitus affects nearly 8 percent of US adults, and its prevalence has been increasing. Antimalarials such as hydroxychloroquine, a long-standing safe and inexpensive treatment for an autoimmune disease such as rheumatoid arthritis, theoretically may improve glucose tolerance and prevent diabetes mellitus, according to background information in the article. In vitro and animal studies indicate that antimalarials improve insulin secretion and peripheral insulin sensitivity. Mary Chester M. Wasko, M.D., M.Sc., of the University of Pittsburgh, and colleagues examined the association between hydroxychloroquine therapy and risk of diabetes in patients with rheumatoid arthritis. During the observation period, incident diagnoses of diabetes were reported by 54 patients who had taken hydroxychloroquine and by 171 patients who had never taken it. Analysis indicated that patients who had taken hydroxychloroquine had a 38 percent lower risk of developing diabetes, compared with those who had not taken hydroxychloroquine.

This risk was further reduced with increased duration of hydroxychloroquine use. Patients who took hydroxychloroquine for more than four years had a 77 percent lower risk of diabetes compared with those who had never taken hydroxychloroquine.

The researchers also said that anti-malarial drugs may have a role in treating rheumatoid arthritis not only to suppress synovitis [inflammation around the joints] but also to reduce the likelihood of developing glucose intolerance and dyslipidemia .