Impact of obesity on rheumatoid arthritis: Relation with disease activity, joint damage, functional impairment and response to therapy

Background and Aim of Work: The impact of Body Mass Index (BMI) on outcomes of Rheumatoid Arthritis (RA) is uncertain. This study aimed to evaluate the influence of obesity on Egyptian patients with RA. Methods: Medical records of 146 RA patients were reviewed. Patients were categorized into normalweight, overweight and obese groups based on BMI. The clinical and laboratory indices of RA activity, the Health Assessment Questionnaire (HAQ) and the radiographic damage score were compared among the groups at baseline, 8, 16 and 24 months. Results: DAS28 and HAQ score were matched at baseline but improved in the 3 groups thereafter, however, differences among the groups become significant only at 24-month. At the 24-month, DAS28 was significantly better in normal-weight (2.1 ± 1.0) and in overweight groups (2.2 ± 0.8) compared to obese group (2.7 ± 1.0) (normal-weight vs obese p=0.003 and overweight vs obese p= 0.006). At the 24-month, HAQ score was significantly better in normal-weight (0.78 ± 0.6) and in overweight groups (0.82 ± 0.5) compared to obese group (1.09 ± 0.7) (normal-weight vs obese p= 0.16 and overweight vs obese p= 0.041). The radiological Sharp-van der Heijde Score along the study period was lower in obese than in overweight or normal-weight patients, albeit the differences in the radiological score were insignificant among the groups. Conclusion: Obese patients were shown to have a poorer response rate to treatment in all outcome measures in comparison to the overweight and the normal-weight RA patients. Future research work is required to investigate whether weight reduction can decrease non-remission rate among the obese RA patients.