To evaluate the association between body mass index (BMI) and tumor necrosis factor α (TNF-α) blockers retention in patients with rheumatoid arthritis (RA).
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%.
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.
Morbid obese RA patients have lower TNF-α blocker retention compared to normal weight patients.