Objectives To analyze insulin resistance (IR), inflammatory cytokines, adipokines and clinical and laboratory characteristics in patients with early rheumatoid arthritis (ERA) who have not received any treatment for their disease.
Methods This is a cross-sectional study based on cases and controls. Forty six consecutively adults (age ≥16 years old) with ERA (disease duration <1 year) according to 2010 ACR/EULAR criteria, and 45 sex and age matched controls were included. Patients with Diabetes (2010 ADA Criteria) or in treatment with glucocorticoids or DMARDs (current or previous) were excluded. All participants signed an informed consent. Glucose, lipid profile, RF, antiCCP and ESR were measured; insulin, ultrasensitive CRP, IL6, TNFα, Resistin, adiponectin, and leptin were determined in frozen serum stored at -80°C. Insulin Resistance (IR) was estimated by the Homeostasis model assesment for insulin resistance (HOMA-IR), by HOMA β, by McAuley and by QUICKI index. A cardiovascular risk factors (CVRF) questionnaire was also completed. Measurement of waist and hip circumference was performed. Statistical analysis: Comparisons between groups were performed using Chi-square, T-test or Mann Whitney test. Pearson or Spearman´s correlation analysis was used for estimating correlation between quantitative variables.
Results 103 subjects were investigated. 12 were excluded (6 were other types of arthritis, 6 were Diabetics) and finally, 91 subjects were included in the study; 46 were patients with RA and 45 were healthy controls. Most of them were women (76.1% in RA). Cases and controls were similar in age, sex and BMI. Regarding characteristics of patients with RA, the mean time duration of RA was 5,9 (SD± 3,5) months, and more than 70% of patients had positive RF and/or AntiCCP. CRP and ESR were higher in RA patients than in controls (p<0,001). Differences were found in values of total cholesterol, which were higher in controls [215 mg/dl Vs 195 mg/dl (p=0,024)], HDL levels were lower in RA patients [52 mg/dl Vs 59 mg/dl (p=0,044)], hypertension was observed in a larger number of patients with RA [30.4% vs. 13.3% (p=0,049)]. Cytokines levels, such as IL6, TNF-alpha were higher in RA patients too. Serum Resistin levels were higher in RA patients but no differences were found in leptin, adiponectin or atherogenic index, HOMA-RI, HOMA β, QUICKI or MCauley index. Bivariate analysis revealed a statistically significant correlation between the different indices of IR and parameters of inflammatory activity (PCR, TNF), leptina and body composition. In multiple linear regression noted a positive correlation between HOMA IR and AR evolution time to diagnosis in months.
Conclusions The patients with untreated very early RA still do not show insulin resistant observed in patients with established RA despite having high levels of DAS28, CRP, ESR, IL6, TNF-alpha, and resistin. Lack of association between AR and IR indexes might be due to the short course of the disease
Disclosure of Interest None Declared