Objectives Obesity has been proposed as a risk factor for refractory rheumatoid arthritis (RA). We evaluated the impact of obesity on achieving clinical and imaging definitions of low disease activity.
Methods This study evaluated 470 patients with RA from GO-BEFORE and GO-FORWARD randomised clinical trials. Included patients had blinded clinical disease activity measures and MRI at baseline, 24 and 52 weeks. Synovitis, osteitis and total inflammation scores were determined using the RA MRI scoring system. Multivariable logistic regression analyses compared odds of achieving Disease Activity Score using 28 joints and C-reactive protein (DAS28-CRP) remission, low component measures, or low MRI inflammation measures at 24 weeks in patients with obesity versus no obesity.
Results At 24 weeks, patients with obesity were significantly less likely to achieve DAS28(CRP) remission (OR 0.47; 95% CI 0.24 to 0.92, p=0.03). In contrast, patients with obesity had similar odds of achieving low synovitis (OR 0.94; 95% CI 0.51 to 1.72, p=0.84) and inflammation scores (OR 1.16; 95% CI 0.61 to 2.22, p=0.64) and greater odds of achieving low osteitis scores (OR 2.06; 95% CI 1.10 to 3.84, p=0.02) versus normal weight patients.
Conclusions Patients with RA and obesity have lower rates of DAS28 remission but similar rates of low MRI activity compared with patients without obesity, suggesting that obesity and its associated comorbidities can bias clinical disease activity measures.
Trial registration number NCT00361335 and NCT00264550; Post-results.
- Rheumatoid Arthritis
- Disease Activity
- Magnetic Resonance Imaging
- Outcomes research
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Contributors All authors were involved in the study design, data collection and interpretation and approved the final version of the manuscript. MG and JB performed the statistical analyses and wrote the manuscript with input from the coauthors.
Competing interests PGC has done speakers bureaus or consultancies for AbbVie, BMS, Janssen, Lilly, Novartis, Pfizer and Roche. PE has received consulting fees, speaking fees and/or honoraria from Pfizer, Merck, AbbVie, UCB, Roche, BMS, Lilly and Novartis (less than US$10,000 each). DGB is an employee of Janssen Biotech. M Østergaard has received fees for consultancy or speaker fees and/or research support from Abbott, AbbVie, BMS, Boehringer-Ingelheim, Celgene, Centocor, Eli-Lilly, GlaxoSmithKline, Hospira, Janssen, Merck, Mundipharma, Novartis, Novo, Orion, Pfizer, Regeneron, Sanofi, Schering-Plough, Roche, UCB, Takeda and Wyeth.
Provenance and peer review Not commissioned; externally peer reviewed.