Objective: To investigate obesity and insulin resistance and associated factors in patients with rheumatoid arthritis (RA).
Methods: We included a cohort of patients with RA. In the clinical research, duration of disease, existence of clinical remission (disease activity index [DAS] 28 below 2.6) and amount of the relevant disease-modifying anti-rheumatic drugs were derived from clinical datum. Cumulative corticosteroid dose was calculated by duration of corticosteroid usage and ratio of physiologic dose. Insulin resistance was calculated with the homeostasis model of assessment of insulin resistance.
Results: A total of 64 patients aged between 22 and 77 with RA were studied. Insulin resistance was detected in 34.4% (n = 22) of patients. There was a statistically significant correlation between body mass index and DAS28 scores (r = 0.469, p = 0.000). We found that the incidence of insulin resistance was lower in patients treated with methotrexate at least 1 year (p = 0.001). As long as we did not detect insulin resistance, none of the patients (n = 7) treated with tumour necrosis factor (TNF) blockers. Cumulative steroid dose, presence of obesity and DAS28 were the best predictors for insulin resistance according to multivariate linear regression analysis (R2c = 0.242, F = 6.39, p < 0.001). In this model R2c for cumulative steroid dose was 0.113 (F = 7.88, p < 0.007) and obesity was 0.147 (F = 10.67, p = 0.02).
Conclusion: Obesity and long-standing corticosteroid usage were determinants of insulin resistance in patients with RA. Medications such as methotrexate, TNF blockers may help to reduce insulin resistance.