We examined the risk of DM among subjects with rheumatoid arthritis (RA), psoriatic arthritis or psoriasis (PsA/PsO), compared with non-rheumatic controls.
We assembled study cohorts using linked health care utilization data from British Columbia. All persons with at least two diagnoses of RA or PsA/PsO were included and compared with a cohort of persons without any known rheumatic disease. The outcome of interest was a diagnosis of new onset DM, as defined by initiation of an anti-diabetic medication. Incidence rates (IR) per 1,000 person-years and incidence rate ratios (IRR) were calculated and Cox regression models examined to determine the hazard ratio (HR) for diabetes by age, gender, systemic immunosuppressive and glucocorticoid use.
The study cohort consisted of 48,718 subjects with RA, 40,346 with PsA/PsO, and 442,033 without any rheumatic disease. The IR for DM among subjects with RA was 8.6 per 1,000 person-years (95% CI 8.5 – 8.7), PsA/PsO 8.2 (95% CI 8.1 – 8.3), and for non-rheumatic controls 5.8 (95% CI 5.8–5.8). The adjusted HR for RA compared with non-rheumatic controls was 1.5 (95% CI 1.4–1.5) and 1.4 (95% CI 1.3 – 1.5) for PsA/PsO.
RA and PsA/PsO appear to be associated with an increased risk of DM. The ability of potent anti-rheumatic treatments to reverse this trend warrants study.