P469. Influence of bodyweight on response to adalimumab treatment in patients with Crohn's disease
E. Leo Carnerero1, J.M. Alcivar Vasquez1, C. Trigo Salado1, D. De la Cruz Ramírez1, F. Domínguez Abascal1, J.M. Herrera Justiniano1, J.L. Márquez Galán1, 1HU Virgen del Rocío, Digestive diseases, Seville, Spain
Unlike with infliximab, adalimumab (ADA) dosage is constant in all patients regardless of bodyweight. Our objective was to determine whether the weight of the patient has an influence on ADA treatment in patients with Crohn's disease (CD) in such a way that heavier patients would require an increase in ADA dosage.
Retrospective study of 73 patients with CD who were treated with ADA between May 2006 and January 2011 with subsequent follow-up of at least 1 year. We exclude 5 patients because of side effects.
We collected the following data: gender, weight, body mass index (BMI), smoking, phenotypic characteristics of CD, treatments used prior to and during ADA use, indication and induction treatment dosage, endoscopy and CRP levels prior to starting (not in all subjects) and hospital admissions, surgical interventions and need for steroids after treatment.
We analyze the rate of treatment failure with ADA in the first year of follow-up based on the patient's weight. A treatment failure was defined as discontinuing treatment at the physician's discretion whether it was to leave the patient without biological treatment, to change biological treatment or for a surgical intervention.
The mean weight was 71.04 kg and the mean BMI 24.88 kg/m2. Treatment failure occurred in 24/68 patients (35.3%; 2/3 in patients with induction dosage of 160/80 mg).
The body weight of patients who failed treatment on ADA is lower (63.62 vs 75.09 kg, p 0.01). If a patient weights more than 70 kg, the risk of failure is lower (OR 0.24 [0.07–0.75; p 0.01]). Among the other factors analyzed, we found a poorer response if patients need for steroids when starting ADA (OR 2.91 [1.00–8.42; p 0.04]) and BMI less than 20 kg/m2 (OR 5.00 [1.31–18.96; p 0.01]), with statistical significance not being achieved for severe endoscopic changes (OR 3.25 [0.78–13.48]). CRP was higher among patients who failed ADA treatment (32.2 vs 12.85 mg/l, p 0.03). Weight had no influence on the number and days of hospital admissions or steroid use but weight <70 kg increases risk of surgery (33.3% vs 11.5%, p 0.04).
Patients with greater bodyweight do not require higher dosages of ADA in order to achieve a response. Paradoxically, the response is poorer in patients with lower body weight, possibly because this reflects a poorer clinical situation at the time of treatment. In fact, these are the patients with a lower BMI, higher CRP, severe endoscopic lesions and a need for steroids at the onset of treatment.