To examine the risk of incident type 2 diabetes mellitus (DM) among patients with rheumatoid arthritis (RA) versus the risk among 4 different comparison cohorts.
Using a large US commercial insurance database, Optum Clinformatics Data Mart (2005-2017), we identified patients with RA based on ≥2 diagnoses for RA and use of ≥1 disease-modifying antirheumatic drug. We selected 4 comparison cohorts with ≥2 disease-specific diagnoses and ≥1 dispensing of disease-specific drugs: 1) general non-RA patients, 2) patients with hypertension, 3) patients with osteoarthritis (OA), and 4) patients with psoriatic arthritis (PsA). The index date was the disease-specific drug dispensing date. Patients with RA were matched to the comparator cohorts (except PsA) for age as of the index date, sex, and index date. The primary outcome was incident type 2 DM, defined as a new diagnosis of type 2 DM plus a new dispensing of antidiabetic drugs. A multivariable Cox proportional hazards model estimated hazard ratios of incident type 2 DM among RA versus each of the comparison cohorts, accounting for >40 baseline covariates.
A total of 449,327 RA, general non-RA, hypertension, OA, or PsA patients were selected. During the median of 1.6 (range 0.6-3.3) years of follow-up, the incidence rate of type 2 DM was the lowest in the RA cohort (7.0 per 1,000 person-years) and highest (12.3 per 1,000 person-years) in the hypertension cohort. After adjusting for >40 baseline covariates, we found that RA was associated with a 24-35% lower risk of incident type 2 DM compared to 4 comparison groups.
In this large population-based cohort study, patients with RA had a lower rate of incident type 2 DM compared to the general non-RA, hypertension, OA, and PsA cohorts.