Background TNF-alpha plays a central role in the pathogenesis of rheumatic diseases and has become a target molecular structure for antibody or TNF-receptor (TNF-R) based treatment in the past few years. Whilst the effects of anti- tumor necrosis factor (anti-TNF) therapy upon disease control are well established in terms of reducing joint inflammation and destruction, its effect on weight remain to be clearly established.
Objectives The aim of this study was to investigate the changes on weight and body mass index in patients with rheumatoid arthritis (RA) and ankylosing spondylitis (AS) treated with anti-TNF.
Methods Thirty-five patients with RA and AS, body weight and body mass index (BMI) were measured before initiation of anti-TNF ( infliximab, etanercept, adalimumab) treatment and after 48 weeks of treatment. BMI was divided into three categories (<20 kg/m2, 20-30 kg/m2, >30 kg/m2).
Results Thirty-five patients were evaluated. 48 weeks after initiation of treatment the mean ± SD weight was increased from 71.31±15.28 kg to 73.11±14.40 kg (p=0.245), the mean ±SD BMI was increased from 25.97±5.86 kg/m2 to 26.51±5.17 kg/m2 (p=0.362). When the BMI was divided into 3 categories, after 48 weeks of treatment, the weight increased in the groups with BMI<20 kg/m2 (45± 5.8 kg to 52± 16.7 kg p=0.285) and BMI 20-30 kg/m2 (71.12±11.07 kg to 74.45±12.31 kg p=0.018). The weight significantly decreased in the group with BMI >30 kg/m2 (87±9.34 kg to 80.57±9.14 p=0.017).
Conclusions Anti-TNF treatment may have and indirect positive effect on lean mass throughout the general health improvement of patients, leading to increase of appetite. Several studies have reported body weight gain in patients with rheumatologic diseases after anti-TNF treatment. We observed that RA and AS patients with lower and normally BMIs tend to gain weight with anti-TNF therapy. In contrast the patients with high BMIs tend to decrease weight with anti-TNF therapy.
Disclosure of Interest None Declared