Role of insulin resistance in increased frequency of atherosclerosis detected by carotid ultrasonography in rheumatoid arthritis.

Abstract

We evaluated the presence of subclinical atherosclerosis and factors influencing atherosclerosis, including insulin resistance (IR), in patients with rheumatoid arthritis (RA). Sixty-three patients with RA and 34 controls were studied. Patients' cardiovascular risk factors were recorded; biochemical variables were determined. Intima-media thickness (IMT) of carotid arteries was determined by B-mode ultrasonography, and presence of atheromatous plaques was determined. IR was calculated according to the HOMA-IR homeostasis model. There were no differences in atherosclerotic risk factors between patients with RA and controls. In the RA group, the median carotid IMT was 0.61 mm (range 0.56-0.74), greater than the 0.54 mm (range 0.50-0.64) in controls (p = 0.01). There was a tendency to a higher frequency of carotid plaques in the RA group compared to controls [12 RA patients (19%) vs 2 controls (5.9%); p = 0.10]. Multivariate regression analysis revealed the factors that had an independent effect on increased carotid IMT: age (p < 0.001), male sex (p = 0.01), and total cholesterol level (p = 0.02). In RA patients with plaques, age (64.5 vs 48 yrs; p = 0.005), carotid IMT (0.75 vs 0.60 mm; p = 0.001), frequency of hypertension (58.3% vs 23.5%; p = 0.03), and IR (83.3% vs 29.4%; p = 0.001) were higher. Multivariate logistic regression analysis showed that factors independently associated with the presence of plaques were IR (OR 15.85, 95% CI 2.23-112.89, p = 0.006) and age (OR 1.11, 95% CI 1.02-1.21, p = 0.02). In RA patients, HOMA-IR correlated with age (r = 0.26, p = 0.04), Health Assessment Questionnaire score (r = 0.28, p = 0.04), and concentrations of triglyceride (r = 0.39, p = 0.003) and cholesterol (r = 0.33, p = 0.02). IR in the setting of active rheumatoid disease may contribute to mechanisms of accelerated atherogenesis observed in patients with RA.