Does weight-adjusted anti-tumour necrosis factor treatment favour obese patients with Crohn's disease?

BACKGROUND

Adalimumab (ADA) is a subcutaneous anti-tumour necrosis factor (anti-TNF) agent, effective in inducing and maintaining remission in Crohn's disease (CD). Unlike Infliximab (IFX), ADA dosing is not weight adjusted and dose frequency is based on clinical response.

OBJECTIVE

To determine whether obesity is a risk factor for early loss of response (LOR) to anti-TNF treatment and whether weight-adjusted anti-TNF treatment is favourable.

METHODS

A hospital database of CD patients receiving anti-TNF treatment was analyzed retrospectively. The relationship between time to LOR and BMI was examined by Kaplan-Meier (KM) survival curves and a Cox proportional hazards model.

RESULTS

ADA patients: Of the 54 patients (46 BMI<30 and 8 BMI≥30), KM estimation indicated a significantly shorter time to dose escalation in the BMI of at least 30 (χ=6.117, P=0.01). The Cox proportional hazards model showed that an increased hazard of LOR to ADA is related to increases in BMI (P=0.04). IFX patients: Of the 76 patients (62 BMI<30 and 14 BMI≥30), KM estimation showed that the differences in survival curves were not significant (χ=1.933, P=0.16) for the BMI groups. This was supported by the Cox proportional hazard model (P=0.36).

CONCLUSIONS

BMI appears to be important in predicting ADA efficacy (LOR) in CD. IFX appears to overcome this reduction of efficacy in obese patients. A prospective study evaluating the effect of weight on anti-TNF drug response and serum drug levels is warranted.