A study published in Arthritis Care & Research provided the first evidence of a similar decrease in therapeutic response with both tumor necrosis factor inhibitors (TNFi) and non-TNFi in severely obese patients.

Data on nearly 6,000 individuals who initiated second- or third-line treatment for rheumatoid arthritis (RA) with TNF- (n = 2,891) or non-TNFi biologics (n = 3,010) between 2001 and April 30, 2021 were included. The study categorized BMI as underweight (less than 18.5 kg/m²), normal weight (18.5-25 kg/m²), overweight (25-30 kg/m²), obese (30-35 kg/m²), and severely obese (35 kg/m² or higher).

None of the biologic medications showed any superiority among patients with RA across different body mass index (BMI) groups, and obesity and underweight both decreased the effects of the treatments 6 months after use.

Severely obese patients had the least chances of achieving either low disease activity (LDA) or a change at least as large as the minimum clinically important difference (MCID), as well as reduced improvement in Clinical Disease Activity Index (CDAI) score from baseline, compared with other BMI categories. Underweight patients had lower odds of achieving LDA (odds ratio, 0.32; P = .005) or a change at least as large as the MCID (OR, 0.40; P = .005) in adjusted models. Lesser improvement was seen in CDAI among underweight patients, compared with normal weight patients (P = .006).(Medscape Medical News, March 27, 2022)