BRIEF REPORT Impact of 24 months of anti-TNF therapy versus methotrexate on body weight in patients with rheumatoid arthritis: a prospective observational study Paolo Sfriso 1 & Francesco Caso 1,2 & Giuseppe Sebastiano Filardo 1 & Costantino Botsios 1 & Luisa Costa 1,2 & Raffaele Scarpa 2 & Silvano Todesco 1 & Paolo Spinella 3 & Francesca Oliviero 1 & Leonardo Punzi 1 Received: 28 July 2015 /Revised: 5 February 2016 /Accepted: 22 March 2016 # International League of Associations for Rheumatology (ILAR) 2016 ABSTRACT To evaluate the impact of anti-TNF-α therapy on the body weight of rheumatoid arthritis (RA) patients fol- lowing 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 in- crease 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. Keywords Anti-TNF alpha . Body mass index . Body weight . Methotrexate . Rheumatoid arthritis Introduction Tumor necrosis factor-α (TNF-α) plays a key role in the path- ogenesis and progression of rheumatoid arthritis (RA) and represents one of the main therapeutic targets in this disease. TNF-α is also involved in the development of rheumatoid cachexia, a complex metabolic syndrome associated with un- derlying illnesses and characterized by loss of muscle with or without loss of fat mass [1, 2]. TNF-α induces muscle loss directly by both stimulating muscle protein breakdown [3] and reducing the sensitivity of skeletal muscle cells to anabolic stimuli. It also induces downregulation of growth factors and anabolic hormones with consequent anorexia and physical inactivity [4]. It has been observed that anti-TNF-α therapy has signifi- cant anti-cachectic effects, promoting the increase of body weight [5, 6] especially in patients with lower body mass index (BMI) [7]. Obesity is a condition of abnormal or excessive fat accumu- lation in adipose tissue as a result of the prevalence of anabolic- orexigenic on catabolic-anorexigenic mechanisms [8]. In general population, BMI is commonly used in both con- ditions to classify underweight and overweight [9, 10]. On the basis of a higher proportion of fat mass in RA patients compared to healthy individuals, Stavropoulos-Kalinoglou de- veloped and validated RA specific BMI cutoff levels (RA- BMI) and algorithms to calculate body fat from BMI [11]. The aim of this study was to evaluate the effects of treat- ment with anti-TNF-α and methotrexate (MTX) on the body weight of RA patients following 24 months of therapy. * Paolo Sfriso paolo.sfriso@unipd.it 1 Rheumatology Unit, Department of Medicine DIMED, University of Padova, Via Giustiniani, n.2, 35128 Padova, Italy 2 Rheumatology Unit, Department of Clinical Medicine and Surgery, University Federico II of Naples, Naples, Italy 3 Clinical Nutrition Unit, Department of Medicine DIMED, University of Padova, Padova, Italy Clin Rheumatol DOI 10.1007/s10067-016-3244-7