Screening prior to biological therapy in Crohn's disease: adherence to guidelines and prevalence of infections. Results from a multicentre retrospective study.

Background: Screening for opportunistic infections prior to starting biological therapy in patients with inflammatory bowel disease is recommended.

Aims: To assess adherence to screening for opportunistic infections prior to starting biological therapy in Crohn's disease patients and its yield.

Methods: A multicentre retrospective study was conducted in Crohn's disease patients in whom infliximab or adalimumab was started between 2000 and 2010. Screening included tuberculin skin test, interferon-gamma release assay or chest X-ray for tuberculosis. Extended screening included screening for tuberculosis and viral infections. Patients were followed until three months after ending treatment. Primary endpoints were opportunistic and serious infections.

Results: 611 patients were included, 91% on infliximab. 463 (76%) patients were screened for tuberculosis, of whom 113 (24%) underwent extended screening. Screening for tuberculosis and hepatitis B increased to, respectively, 90-97% and 36-49% in the last two years. During a median follow-up of two years, 64/611 (9%, 3.4/100 patient-years) opportunistic infections and 26/611 (4%, 1.6/100 patient-years) serious infections were detected. Comorbidity was significantly associated with serious infections (hazard ratio 3.94).

Conclusions: Although screening rates for tuberculosis and hepatitis B increased, screening for hepatitis B was still suboptimal. More caution is required when prescribing biologicals in patients with comorbid conditions.