The epidemiology and influence of osteoarthritis on clinical, laboratory and ultrasound parameters of patients with early rheumatoid arthritis

Background: Osteoarthritis (OA) and rheumatoid arthritis (RA) can overlap and the presence of OA can interfere with the evaluation of patients with RA. Objectives: The aim of this study was to evaluate the possible impact of OA on the clinical, laboratory and ultrasound parameters currently evaluated in patients with early RA (ERA). Methods: We have evaluated the data obtained from patients with ERA referred to our Early Arthritis Research Center (EARC). Only data from patients who fulfilled EULAR/ ACR 2010 criteria for RA and had symptom duration of less than 12 months were analyzed. All patients underwent clinical examination, laboratory tests and ultrasound (US) examination. Results: There was a clear predominance of women (62.8%). The mean age was 55.47±13.71 years. At baseline, 21 patients (48.8%) were diagnosed with OA. Hand OA did not influence the values of any of the parameters assessed (p>0.05). For patients with knee OA, significantly higher values were observed only for DAS28 at baseline (p=0.018) as well as after 12 months of observation (p=0.031). Conclusions: Significantly higher values of DAS28 were observed in patients with ERA who associated knee OA, while the values of SDAI were not influenced, suggesting that SDAI may be superior to DAS28 in evaluating patients with ERA and knee OA. The values of patient’s VAS were not influenced by the presence of hand or knee OA suggesting that these types of OA do not influence the patients’ perception of the disease activity. Moreover, the values of ultrasound scores were not influenced by the presence of OA.