THE CORRELATION OF INSULIN RESISTANCE WITH SERUM TNF ALPHA LEVELS IN PATIENTS WITH RHEUMATOID ARTHRITIS

Objective: The aim of this study was to assess the occurence of acute insulin response and insulin sensitivity changes in patients with rheumatoid arthritis, and to evaluate the correlation of serum TNF-α a level changes with glucose metabolism abnormality such as insulin resistance and impaired acute insulin response. Methods: 36 subjects (22 women and 14 men, aged 51.5 ±17.1 years (range 21-80), BMI 27.1±5.0 kg/m2;) with varying degrees of disease activity and 20 healthy controls were studied. After a 12-h overnight fast, all subjects underwent a diagnostic protocol including serum insulin level, HOMA-IR estimated insulin sensitivity, AIR derived from IVGTT data and serum TNF-α a level measurements. Results: The fasting insulin levels, HOMA scores and serum TNF-α a levels were significantly higher in all patients with rheumatoid artritis than in control subjects (14.7±6.7 vs. 8.7±1.9 mIU/ml, p<0.001 and 3.3±1.5 vs. 1.9±0.5, p<0.001 and 368.4±649.2 vs. 3.6±5.0 pg/ml, p<0.001 respectively). Acute insulin responses were significantly lower in all patients with rheumatoid arthritis than in control subjects (35.8±17 vs. 85.2±17.9, p<0.001). Fasting insulin, HOMA-IR, TNF-α, AIR were correlated in the whole group. Conclusions: Insulin resistance seems to be the main metabolic abnormality which alters glucose metabolism, decreases the sensitivity of peripheral tissues to insulin in patients with rheumatoid arthritis, and complicating rheumatic disease via an increase in atherosclerotic disease risk and prediabetic state.