High Body Mass Index is Associated with Shorter Retention of Tumor Necrosis Factor-Alpha Blocker Treatment in Rheumatoid Arthritis

Ofir Elalouf,1,2 Merav Lidar,2,3 Tatiana Reitblat,4 Devy Zisman,5 Alexandra Balbir-Gurman,6 Odelia Hakakian,1 Tanya Mashiach,7 Ronit Almog,7 Ori Elkayam1,2 1Department of Rheumatology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel; 2Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; 3Rheumatology Unit, The Zabludowicz Center for Autoimmune Diseases, Sheba Medical Center, Ramat Gan, Israel; 4Rheumatology Unit, Barzilai Medical Center, Ashkelon, Israel; 5Department of Rheumatology, Carmel Medical Center, Haifa, Israel; 6Rheumatology Institute; 7Epidemiology and Biostatistics Unit, Rambam Health Care Campus, Haifa, IsraelCorrespondence: Ofir ElaloufDepartment of Rheumatology, Tel Aviv Sourasky Medical Center, 6 Weizmann Street, Tel Aviv, IsraelTel +972524262682Fax +97235422904Email ofire@tlvmc.gov.ilPurpose: To evaluate the association between body mass index (BMI) and tumor necrosis factor α (TNF-α) blockers retention in patients with rheumatoid arthritis (RA).Patients and Methods: This prospective cohort study analyzed data about patients with RA who initiated TNF blockers from the Israeli registry of inflammatory diseases from 2011 to 2019. Patients were grouped by BMI: normal (BMI < 24.9 kg/m2), overweight (BMI 25– 29.9 kg/m2), obese (BMI 30– 34.9 kg/m2) and morbid obese (BMI ≥ 35 kg/m2). Treatment cessation due to inefficacy was defined as an “event” and therapy with a drug above 3 months was defined as a “course.” Kaplan–Meier survival curve was used to describe drug survival. Event-free survival was calculated using Cox regression with a hazard ratio and confidence interval of 95%.Results: The final analysis included 521 RA patients (80% females) treated with etanercept, infliximab, adalimumab or golimumab. Eight hundred and eighteen treatment initiations were included in the final analysis, 334 (41%) in the normal weight group, 261 (32%) in the overweight, 144 (17%) in the obese and 79 (10%) in the morbid obesity group. Three hundred and twenty-six (40%) treatment initiations were with etanercept, 215 (26%) with adalimumab 197 (24%) with infliximab, and 80 (10%) with golimumab. BMI was inversely associated with drug survival. Morbid obese patients were more likely to discontinue treatment compared with normal weight patients HR 2.28 (95% CI 1.67– 3.10, p< 0.01). This association remained significant for each drug type (except for golimumab) in a subgroup analysis. Adalimumab switch rate was higher compared to etanercept with HR =1.51 (95% CI 1.20– 1.91, p< 0.01), no other significant differences were noted between the other drugs.Conclusion: Morbid obese RA patients have lower TNF-α blocker retention compared to normal weight patients.Keywords: TNF alpha, biologics, BMI, obesity, survival