Rheumatoid Arthritis Not Associated With Increased Risk for Type 2 Diabetes Mellitus in Large Cohort Study

Patients with rheumatoid arthritis (RA) had demonstrably lower risk for incident type 2 diabetes mellitus (T2DM) than the general population and patients with osteoarthritis (OA) or psoriatic arthritis (PsA). The results of the study was published in Arthritis Care & Research.

Prior studies have provided inconsistent risk estimates for T2DM in the RA population. Investigators conducted a retrospective, population-based cohort study using claims data extracted from the Optum Clinformatics database for the years 2005-2017. Eligible patients with RA had ≥2 inpatient or outpatient claims with an RA diagnosis and ≥1 claim for any disease-modifying anti-rheumatic drug. For the general non-RA cohort, patients with any non-RA inpatient or outpatient diagnostic code were eligible for inclusion. Patients with hypertension, OA, and PsA were identified based on ≥2 inpatient or outpatient visits with the appropriate diagnostic code and at least 1 dispensing of a disease-specific medication.

Patient groups were mutually exclusive; patients with multiple arthritis diagnoses and/or arthritis with hypertension were excluded. Patients with RA were matched in a 1:1:1: ratio to the general non-RA, hypertension, OA, and PsA groups by age, sex, and date of first medication dispensing claim.

The primary outcome was incident T2DM, defined as having ≥1 inpatient or outpatient diagnosis of T2DM and ≥1 dispensing of an antidiabetic drug. The incident rate of T2DM was calculated for all 5 patient groups. Cox proportional hazard models were used to assess the risk for T2DM in patients with RA vs comparator groups. Models were adjusted for the relevant covariates, including comorbid conditions, T2DM risk factors, medication use, and healthcare utilization.

After matching, the total study cohort comprised 108,568 patients in each of the RA, general non-RA, hypertension, OA, and PsA cohorts. Additionally, data were available from 15,055 patients with PsA. Mean age in the RA, general non-RA, hypertension, and OA cohorts was 55.6 ± 13.5 years, and 77.3% were women. In the PsA group, mean age was 48.6 ± 12.5 years and 48.3% were women. Median follow up time ranged from 1.4 to 1.8 years.

The crude incidence rate of T2DM per 1000 person-years was 7.0 in the RA cohort, 7.4 in the general non-RA cohort, 12.3 in the hypertension cohort, 7.8 in the OA cohort, and 9.9 in the PsA cohort. The adjusted hazard ratios (95% confidence interval [CI]) for incident T2DM in the RA cohort were 0.72 (0.66-0.78), 0.65 (0.60-0.71), 0.75 (0.69-0.81), and 0.76 (0.67-0.86) compared to the general non-RA, hypertension, OA, and PsA cohorts, respectively. In secondary outcome analyses, patients with RA were at elevated risk for hip fractures compared to the hypertension (hazard ratio [HR], 1.30; 95% CI, 1.01-1.60) and general non-RA (HR, 1.33; 95% CI, 1.09-1.64) cohorts.

In this large, population-based study using data from 2005 to 2017, patients with RA had lower risk for incident T2DM than the general population. Diabetes risk was also lower compared to patients with other forms of arthritis.

As study limitations, investigators noted that data on certain diabetes-associated lifestyle factors were not available, such as diet and physical activity. Additionally, disease activity was not measured in any of the arthritis cohorts.

Further study is necessary to confirm these results and delineate the effects of antirheumatic treatment on T2DM risk.

Disclosure: This study was supported by a research grant from Bristol-Myer-Squibb. Please see the original reference for a full list of authors’ disclosures.

Reference

Jin Y, Chen SK, Liu J, Kim SC. Risk of incident type 2 diabetes among patients with rheumatoid arthritis: a population-based cohort study. Arthritis Care Res (Hoboken). 2020;72(9):1248-1256.