There may be an additional bonus for people with rheumatoid arthritis or psoriasis who take certain disease-modifying antirheumatic drugs (DMARDs) to treat the conditions. A study, published in 2011 in the Journal of the American Medical Association, found that several of these drugs – including hydroxychloroquine and TNF-alpha inhibitors – are associated with a reduced risk of developing type 2 diabetes.

“I don’t think we’ve proven [these] drugs are good or bad for diabetes,” says lead researcher Daniel H. Solomon, MD, chief of clinical research in the division of rheumatology at Brigham and Women’s Hospital in Boston. “It may be that people on these drugs have the added benefit of a reduced risk of diabetes, but further studies will help define this issue.”

Type 2 diabetes develops when the body loses its ability to effectively use the insulin it produces. This insulin resistance, as it’s called, results in sugar staying in the bloodstream instead of being stored in cells for energy. It is believed that inflammation plays a role in insulin resistance; people who have systemic inflammatory conditions such as rheumatoid arthritis, or RA, are predisposed to developing insulin resistance.

  The retrospective study tracked nearly 14,000 RA and psoriasis patients, with an average follow-up of almost six months, after they started one of four groups of DMARDs:

  • the biologic TNF-alpha inhibitors etanercept, or Enbrel; adalimumab, or Humira; and infliximab, or Remicade – with or without other DMARDs
  • methotrexate – with or without other non-biologic DMARDs but without TNF-alpha inhibitors or hydroxychloroquine sulfate
  • hydroxychloroquine sulfate, or Plaquenil – with or without other non-biologic DMARDs but without TNF-alpha inhibitors or methotrexate
  • other non-biologic DMARDs, including sulfasalazine, or Azulfidine; leflunomide, or Arava; and cyclosporine or Sandimmune – without TNF-alpha inhibitors, methotrexate or hydroxychloroquine sulfate

During the study period, there were 267 new cases of diabetes among subjects. When researchers sorted through that data, they found that the risk of developing type 2 diabetes was lower among those on TNF-alpha inhibitors and hydroxychloroquine compared with the other categories. There was also a reduced risk among those on methotrexate, but it was not statistically significant. Study subjects treated with other non-biologic DMARDs had the highest rate of newly diagnosed diabetes among the four groups.