BACKGROUND:

Infliximab (IFX) is effective in inducing and maintaining remission in patients with luminal and anoperineal Crohn's disease (CD). However, treatment failure within 12 months after initiating IFX is observed in a significant proportion of patients. The aim of the present study was to determine whether the body mass index (BMI) affects response to IFX during the first year of treatment in patients with CD.

METHODS:

All patients with luminal CD who began IFX between January 2010 and May 2014 were prospectively included. BMI was calculated before IFX treatment was begun, and patients were divided into 3 groups: normal BMI (BMI < 25 kg/m), overweight patients (BMI of 25.0-30 kg/m), and obese patients (BMI > 30.0 kg/m). The primary outcome was to evaluate the rate and delay of IFX optimization during the first year of treatment among normal weight, overweight, and obese patients.

RESULTS:

One hundred forty patients were included. Demographic and clinical characteristics at IFX initiation were comparable among the 3 groups. Within 12 months after the initiation of IFX, the rate of IFX optimization was significantly higher in overweight and obese patients than in the normal BMI group: 52%, 56%, and 20%, respectively (P = 0.0002). The median time until optimization of IFX was significantly shorter in overweight and obese patients than in the normal BMI group: 7, 7, and 10 months, respectively (P = 0.03). A BMI >25 kg/m was significantly associated with IFX optimization within 12 months on multivariate analysis.

CONCLUSION:

This is the first study to show that optimization of IFX is more frequent and faster in obese and overweight patients with CD and occurs within 12 months after beginning IFX, suggesting that an induction regimen with higher doses of IFX and a tight control of IFX concentrations may be needed in these patients.