Patients with type 2 diabetes mellitus (T2DM) have a reduced risk for rheumatoid arthritis (RA), which may be due to statin use, according to a study published in Rheumatology. Researchers conducted a retrospective cohort study to compare RA risk and explore the role of glycemic control in RA risk. A total of 224,551 newly diagnosed patients with T2DM were matched to 449,101 patients without T2DM and were followed to assess RA risk. The incidence rates for RA were 8.1 and 10.6 per 10,000 person-years in the exposed and unexposed groups, respectively, during the study period (adjusted hazard ratio [aHR], 0.73; 95% confidence interval [CI], 0.67 to 0.79). The aHR was 0.89 (95% CI, 0.69 to 1.14) in patients who had not used statins in their lifetime. When quantifying the effects of glycemic control, antidiabetic drugs, and statins, no significant associations were seen for glycemic control, metformin use, and dipeptidyl peptidase-4 inhibitors with RA development. However, among those with T2DM, a protective effect was seen for statins with progression of RA (aHR, 0.76; 95% CI, 0.66 to 0.88), with evidence of a duration-response relationship.