Impact of 24 months of anti-TNF therapy versus methotrexate on body weight in patients with rheumatoid arthritis: a prospective observational study

To evaluate the impact of anti-TNF-α therapy on the body weight of rheumatoid arthritis (RA) patients following 24 months of treatment. Data were collected on all RA patients included in the Veneto Region's Registry of Biological Therapy from January 2007 to July 2012. Inclusion criteria were: start of monotherapy with adalimumab, etanercept, or methotrexate, no previous use of biologic therapy, and at least 24 months of treatment. At baseline, 12, and 24 months, each patient completed a questionnaire about physical activity, smoking, alcohol, and food habits. One hundred and thirty-one RA patients in monotherapy with etanercept (n = 47), adalimumab (n = 44), and methotrexate (n = 40) were enrolled for this study. After 24 months of therapy, there was an increase of weight only in patients treated with anti-TNF-α. Patients on etanercept and adalimumab therapy showed a risk to gain weight six times greater compared to those on methotrexate therapy. The results of present study show that the use of anti-TNF-α in RA patients can be associated to a significant increase of body weight. This increase is not shown in patients under treatment with methotrexate. A more careful evaluation of weight changes needs to be considered in RA patients under anti-TNF-α treatment.