Background Recent studies have suggested that obesity may reduce the response rate to TNFα blockers (1,2).
Objectives The objective of this study was to determine whether body mass index (BMI) affects drug survival of Tumor Necrotic Factor (TNF)-α blockers in patients suffering from rheumatoid arthritis (RA), psoriatic arthritis (PsA) and ankylosing spondylitis (AS).
Methods The data were extracted from the prospective Israeli registry for use of biological agents in patients treated with TNF-α blockers for RA, PsA and AS. Patients were divided according to the baseline BMI as normal BMI (BMI <25), overweight (BMI 25-30, 30-35) and obese (BMI>35). The drug survival was analyzed using the Kaplan-Meier curves. The influence of different covariates on drug survival was analyzed by Cox regression.
Results 574 patients (344 patients with RA, 131 with PSA and 99 with AS) from four Israeli Academic center for rheumatic diseases received 1218 treatment series (etanercept-305, adalimumab-244, infliximab -257); 635 of them were discontinued (391 (62%) because of loss of efficacy. The distribution of BMI was higher but not statistically significant in PsA (median 27.4, IQR 24,3-30.8) in comparison with RA (26.2,23.4-30.5) and AS (26.8,24.1-30.1). Significant overall correlation was found between BMI and biologic treatment effectiveness survival (log-rank p=0.022) for all biologics (non-anti TNF α agents) and (log-rank p=0.011) for anti TNF-α agent particularly. Looking at each of the 3 anti-TNF- α agent separately the association was significant for etanercept drug survival (log-rank p=0.028) but not for Infliximab or adalimumab. Etanercept median survival was 1343, 961, 700, and 580 days for BMI <25,25-30,30-35, and >35 respectively.
Conclusions Increased BMI significantly decreases the drug survival of etanercept in patients with AS, RA, and PsA. Our study results provide basis to suggest that in patients with increased BMI, etanercept should not be recommended as the 1st TNF α blocker
Iannone F, Fanizzi R, Notarnicola A, Scioscia C, Anelli M, Lapadula G. Obesity reduces the drug survival of second line biological drugs following a first TNF-α inhibitor in rheumatoid arthritis patients. Joint Bone Spine. 2015 Jan 22
Gremese E, Bernardi S, Bonazza S, Nowik M, Peluso G, Massara A et al. Body weight, gender and response to TNF-α blockers in axial spondyloarthritis. Rheumatology (Oxford). 2014 May;53(5):875-81
Disclosure of Interest None declared