Obesity reduces the response rate to anti TNFα in rheumatoid arthritis. an approach to a personalized medicine

OBJECTIVE.: Obesity is a mild, long-lasting inflammatory disease and, as such, could increase rheumatoid arthritis (RA) inflammatory burden. The study aim was to determine whether obesity represents a risk factor for a poor remission rate in RA patients requiring anti-TNFα therapy for progressive and active disease despite Methotrexate or other DMARDs treatment. METHODS.: Patients were identified from fifteen outpatient clinics of university-hospitals and hospitals in Italy, taking part in the GISEA (Gruppo Italiano Studio Early Arthritis) network. Disease activity score (DAS28 joints), body mass index (BMI: categorized as a BMI <25, BMI 25-30 and BMI >30), acute phase reactants, rheumatoid factor IgM, anti-cyclic citrullinated peptide, values were collected. DAS28 remission was defined as a score <2.6 lasting for at least 3 months. RESULTS.: 641 outpatients with long standing RA, receiving anti-TNFα blockers (Adalimumab, n=260; Etanercept, n=227; Infliximab, n=154), recruited from 2006 to 2009 and monitored for at least 12 months, were analyzed. The DAS28 at the baseline was 5.6±1.4. A BMI value >30 was recorded in 66 out of 641 RA patients (10.3%). After 12 months of anti-TNFα treatment, a DAS28<2.6 was noted in 15.2% of the obese subjects, in 30.4% of the patients with a BMI 25-30 and in 32.9% of the patients with a BMI<25 (p=0.01). The lowest percentage of remission, statistically significant versus adalimumab and etanercept (p=0.003), was observed with infliximab. CONCLUSIONS.: Obesity represents a risk factor for a poor remission rate in long standing RA treated with anti-TNFα. A personalized treatment might be a possible solution.