Azathioprine use in inflammatory bowel disease in South Durham – an insight into clinical practice

Abstract

Azathioprine is the most common immunosuppressant used in the management of inflammatory bowel disease (IBD). Most of the available data on the effectiveness of this drug emerge from large university teaching hospitals, where there is a referral bias towards complex patients combined with a need for specialist expertise and early initiation of therapy. There are limited data on the use of azathioprine in district general hospitals in the UK, particularly related to efficacy and side effect profile, with concerns about its safety potentially contributing to a reluctance to commence treatment with the drug until late in the course of the disease. This audit was a retrospective case note review of patients attending gastroenterology clinics in South Durham over a decade (1997–2007). The population of the region is 250,000. The Rotherham IBD Database for County Durham was used to identify patients who had ever been exposed to azathioprine. Efficacy and side effect profile were determined. Remission was defined as being steroid-free at 12 months after starting azathioprine. Relapse was defined as active disease requiring steroids or surgical intervention after starting azathioprine. Of 400 patients with IBD, 58 were treated with azathioprine over the ten-year period (13.1%), 29/318 with ulcerative colitis (9.1%), and 29/82 with Crohn’s disease (35.4%). Overall, 21/58 (36.2%) patients were found to be steroid-free within a mean period of five months’ treatment. Among factors favouring response to treatment, a disease phenotype of Crohn’s disease was the only significant one; age, sex, disease distribution and dose were not significant. 27.6% patients relapsed despite treatment, with the relapse rate being lower in ulcerative colitis. Although 47% patients reported some side effect, myelotoxicity was recorded in only 12%. This audit reflects the efficacy and safety of azathioprine when used in the district hospital setting, comparable to larger tertiary centres. Overall, the use is lower than at specialist centres, but this is likely to change with time.