Background Adipose tissue is not inert, but has a not yet clearly understood immunomodulating effect and may adversely impact treatment response in patients receiving anti-TNF therapy1.
Objectives To ascertain the impact of Body mass Index (BMI) on efficacy of anti-TNF therapy.
Methods At the outpatient clinic in Amsterdam, the Netherlands, 853 consecutive patients were included who started with TNF blocking therapy adalimumab (411) or etanercept (442).
Results The average BMI was 26.0 (SD: 5.2, range 14-50). The baseline DAS was high at 4.9 (SD: 1.3). Mean age was 54 years (SD: 13) and 682 (80%) were female. Median follow-up was 2.1 years (IQR 0.7-4.4 years), 2337 patient years total. Nearly half (407, 48%) of patients were of healthy weight according to the WHO criteria (BMI 18.5-25), 257 (30%) of the patients were overweight, and another 168 (20%) were obese (BMI of 25-30, and >30 respectively). Few patients (21, 2%) were underweight (BMI<18.5). Overall, the patients with healthy weight responded best to TNF treatment, followed by overweight and the underweight groups. The group who performed worst was the obese group (see Figure 1). After one year the overweight group had a significantly higher mean DAS28 than the normal weight group (3.0 (1.3) vs. 2.6 (1.2), p=0.005), and the obese group did significantly worse than either (3.4 (1.4), p=0.000 (vs. normal) and 0.026 (vs. overweight)). The DAS 28 at one year of the underweight group did not differ significantly from any other weight group. In regression analysis baseline BMI had a significant effect on the DAS28 at 52 weeks (B=0.054, 95% CI: 0.033-0.075, p=0.000), even corrected for baseline DAS (B 0.036, CI: 0.0018-0.055, p=0.000).
Conclusions Our findings support the hypothesis that adipose tissue may be involved in RA pathophysiology. This is important as it may have implications not only for RA, but also for other immune-mediated inflammatory conditions treated with TNF alpha blocking therapy.
Gremese E, Carletto A, Padovan M, Atzeni F, Raffeiner B, Giardina AR, Favalli EG, Erre GL, Gorla R, Galeazzi M, Foti R, Cantini F, Salvarani C, Olivieri I, Lapadula G, Ferraccioli G. Obesity and reduction of the response rate to anti-tumor necrosis factor α in rheumatoid arthritis: An approach to a personalized medicine. Arthritis Care Res (Hoboken). 2013 Jan;65(1):94-100.
Disclosure of Interest None Declared