Hydroxychloroquine (Plaquenil) is a commonly used disease modifying anti-rheumatic drug (DMARD) for RA that has known beneficial effects on blood glucose and lipids. However, whether its use can prevent the onset of diabetes in RA patients prescribed it to reduce articular signs and symptoms has not been evaluated. Here, Wasko et al (JAMA 2007; 298: 187) explore this issue using prospective data from the Arthritis, Rheumatism, and Aging Medical Information System (ARAMIS) database.
Methods and Results:
Results as published from his study were summarized as presented at the 2006 American College of Rheumatology Meeting.
In a large cohort of RA subjects, any exposure to HCQ was protective against incident self-reported diabetes, independent of confounding factors.
These are interesting results that suggest an added benefit of HCQ use in RA and suggest a link between the immune system and the pathogenesis of Type II diabetes. The exact mechanisms of HCQ efficacy in RA is unknown, but recent data suggests that inhibition of signaling through Toll-like receptors, a participant in innate immune responses, may be a possible mechanism. Whether inhibition of Toll-like receptors by HCQ is also the mechanism of prevention of incident diabetes has not been established.
It should be pointed out that the incidence of diabetes was not especially high in the cohort enrolled in this study, and the prevalence of diabetes has not been found to be increased in RA patients. Thus, HCQ would not be used solely for the prevention of incident diabetes in RA, but should have some basis in controlling articular signs and symptoms. However, combination therapies with HCQ in RA have been shown to be more efficacious than monotherapies. This, coupled with the low toxicity of HCQ in general, is additional reasons not to discourage the liberal use of HCQ in RA patients.