Body Mass Index Impact on Disease Activity, Clinical and Sonographic Remission Rates in Patients with Rheumatoid Arthritis

Aim: To investigate the impact of body mass index (BMI) on clinical disease activity indices and clinical and sonographic remission rates in patients with rheumatoid arthritis (RA). Patients and Methods: Sixty-three patients with RA were categorized according to BMI score into three groups: normal (BMI<25), overweight (BMI25-30) and obese (BMI >= 30). Thirty-three of them were treated with conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs), and 30 with biologic DMARDs (bDMARDs). Patients underwent clinical and laboratory assessment and musculoskeletal ultrasound examination (MSUS) at baseline and at 6 months after initiation of therapy. We evaluated the rate of clinical and sonographic remission (defined as Power Doppler score (PD) = 0) and its correlation with BMI score. Results: In the csDMARDs group, 60% of the normal weight patients reached DAS28 remission; 33.3% of the overweight; and 0% of the obese patients. In the bDMARDs group, the percentage of remission was as follows: 60% in the normal weight subgroup, 33.3% in the overweight; and 15.8% in the obese. Within the csDMARDs treatment group, two significant correlations were found: BMI score-DAS 28 at 6th month, r(s) = .372, p = .033; BMI score-DAS 28 categories, r(s) = .447, p = .014. Within the bDMARDs group, three significant correlations were identified: BMI score-PDUS at sixth month, r(s) = .506, p = .004; BMI score-DAS 28, r(s) = .511, p = .004; BMI score-DAS 28 categories, r(s) = .592, p = .001. Sonographic remission rates at 6 months were significantly higher in the normal BMI category in both treatment groups. Conclusion: BMI influences the treatment response, clinical disease activity indices and the rates of clinical and sonographic remission in patients with RA. Obesity and overweight are associated with lower remission rates regardless of the type of treatment.