Certain DMARDs associated with an increased incidence of diabetes in patients with psoriasis or RA

In patients with psoriasis or rheumatoid arthritis (RA), the use of tumor necrosis factor (TNF) inhibitors or hydroxychloroquine, but not methotrexate, was associated with a decrease in the incidence of diabetes compared to other disease-modifying antirheumatic drugs (DMARDs).

These were the findings of a new cohort study published in JAMA.

In this observational study, researchers identified a cohort of adult patients diagnosed with either psoriasis or RA within 2 health insurance databases, 1 each in Canada and the United States. Eligible participants must have been diagnosed based on ≥2 visits ≥7 days apart, continuously enrolled in the insurance plan for 12 months prior to the diagnosis, and filled at least 1 prescription for a DMARD after the diagnosis. Participants were stratified into 1 of 4 DMARDs groups (TNF inhibitors, methotrexate, hydroxychloroquine, and other nonbiologic DMARDs). Diagnosis of diabetes was identified with diagnosis codes in combination with a new prescription for a diabetes-specific medication.

In their paper the researchers noted, "Taken in the context of prior research, the current study supports the potential role for systemic immunosupression in prevention and control of diabetes." They further emphasized, "The balance of risks and benefits would likely differ across clinical scenarios. For example in individuals without diabetes or a systemic rheumatic disease, use of a potent immunosuppressive may carry more risk than benefit. However, if an individual also has a systemic rheumatic disease for which a DMARD may be indicated, the ratio may shift toward benefits over risks."

Researchers noted several study limitations in their paper including its observational study design, residual confounding, possible misclassification of diabetes, and lack of differentiating type 1 and type 2 diabetes. However, researchers concluded this study to be hypothesis generating and suggest a randomized controlled trial to test this hypothesis further.

This trial was sponsored by Amgen, manufacturers of 1 of the evaluated TNF inhibitors, etanercept (Enbrel).

SOURCE

Solomon DH, Massarotti E, Garg R, Liu J, Canning C, Schneeweiss S. Association between disease-modifying antirheumatic drugs and diabetes risk in patients with rheumatoid arthritis and psoriasis. JAMA. 2011;305:2525–2531.