P437 Risk of immunomediated adverse events or secondary loss of response to infliximab in elderly patients with inflammatory bowel disease: a cohort study of the ENEIDA registry

Abstract Background Infliximab is one of the most used biological drugs in inflammatory bowel disease (IBD). Immunomediated adverse events (IAE) are of the most frequent reported infliximab-related adverse events. Elderly patients have differential pharmacodynamic and pharmacokinetic characteristics. We recently reported an increased risk of thiopurine-related AEs in this population; hence, it would be relevant to ascertain if combined treatment is adequate in this population. Our aim was to evaluate the rate of infliximab-related IAE in elderly IBD patients. Methods All adult patients in the ENEIDA registry (a large, prospectively maintained database of the Spanish Working Group in IBD–GETECCU) who received a first course of infliximab treatment were identified. Patients were selected in two cohorts regarding the age at the beginning of infliximab treatment: over 60 years, and between 18 and 50 years of age. The rates of IAE recorded in the ENEIDA database (infusion reactions, delayed hypersensitivity, oedema, allergy, anaphylaxis, psoriasis, lupus-like syndrome) were compared, as well as the rate of secondary loss of response (SLR). Results We included 939 (12%) patients who started infliximab over 60 years and 6844 (88%) patients below 50 years. The rate of IAE (15% vs. 15%, ns) and treatment withdrawal due to IAE (13% vs. 12%, ns) was similar in both groups. Neither differences were observed according to IAE: infusion reactions (8.3% vs. 8.2%), late hypersensitivity (1.4% vs. 1.2%), paradoxical psoriasis (0.9% vs. 1.4%) and drug-induced lupus erythematosus (0.7% vs. 0.6%). Patients below 50 years were significantly more often treated with concomitant immunosuppressants (57% vs. 48.1% >60 years, p < 0.05). In the multi-variate analysis, combination with immunosuppressants (OR 0.741; 95% CI 0.64–8.5, p < 0.05) and female sex (OR 1.8; 95% CI 1.6–2.1, p < 0.05) were the only independent predictors to develop IAE. The rate of SLR was also similar in both study groups (20% vs. 21%). Combination therapy with immunosuppressants was the unique risk factor to develop SLR (OR 0.85; CI 95% 0.73 to 0.98, p = 0.021). Conclusions Elderly IBD patients who start treatment with infliximab have a similar risk of developing IAE and SLR than younger patients. From this point of view, elderly would benefit from combination therapy.