The clinical implication of drug dependency in children and adults with inflammatory bowel disease: a review

Drug dependency in adult and paediatric patients with inflammatory bowel disease (IBD) is described and the significance of this response pattern in clinical practice discussed in this review. Dependent patients maintain remission while on the treatment, but they relapse shortly after drug cessation or dose decrease. However, a quick restoration of remission and sustained response is achieved when the therapy is re-introduced or dose increased. Population-based studies have demonstrated that 22-36% of adults and 14-50% of children become corticosteroid dependent. Approximately 1/4-1/3 of treated patients undergo surgery ≤1 year after treatment start, although newer paediatric studies reported lower risk of surgery (5-11%), including dependent patients. The frequent use of immunosuppressants (68-80% of children) might explain this favourable outcome and thus reduce importance of the term corticosteroid dependency. Infliximab dependency was described in 42-66% of children and 29% of adults with Crohn's disease. The risk of surgery 50 and 40 months after treatment start was 10% and 23% in infliximab dependent children and adults, respectively. Maintenance of infliximab in dependent patients was suggested to postpone if not avoid the need of surgery. Lastly, mesalazine dependency was identified in 23% of adults with Crohn's disease. These patients were characterized by mild disease course and lower surgical risk compared to non-responders to mesalazine (32 vs. 61%). Identification of drug dependency is useful for prediction of a certain disease course and surgery. An adjustment of medical therapy may alter the prognosis and disease course.