Differences in the prevalence and characteristics of metabolic syndrome in rheumatoid arthritis and osteoarthritis: a multicentric study

The purpose of the study was to examine whether rheumatoid arthritis (RA) patients have higher prevalence of metabolic syndrome (MetS) than osteoarthritis (OA) patients in association with a higher level of chronic systemic inflammation in rheumatoid arthritis. A total of 583 RA and 344 OA outpatients were analyzed in this multicentric study. Metabolic syndrome was defined using the National Cholesterol Education Program Adult Treatment Panel III criteria. A 1.6-fold higher prevalence of MetS was found in patients with OA compared with the RA patients. Among the parameters of MetS, patients with OA had significantly higher levels of waist circumference, systolic blood pressure, fasting blood glucose and triglycerides, whereas HDL cholesterol and diastolic blood pressure values were similar in both groups of patients. Higher values of inflammatory markers [C-reactive protein (CRP), erythrocyte sedimentation rate (ESR)] in MetS than in non-MetS patients and higher prevalence of MetS in patients with CRP level ≥5 mg/L in both RA and OA patients were found. In multivariate logistic regression analysis, significant predictors of MetS were type of arthritis (OA vs. RA; OR 2.5 [95 % CI 1.82–3.43]), age (OR 1.04 [95 % CI 1.03–1.06]) and ESR (OR 1.01; [95 % CI 1.00–1.01]). The significant association between OA and MetS was maintained in the regression model that controlled for body mass index (OR 1.87 [95 % CI 1.34–2.61]). The present analysis suggests that OA is associated with an increased risk of MetS, which may be due to a common underlying pathogenic mechanism.