Retrospective case series analysis of patients with inflammatory bowel disease on azathioprine. A district general hospital experience

Abstract

Objectives: The aim of this study was to look at our practice of using azathioprine and to compare our results with those in published trials both from the point of view of response and also the side-effect profile.

Design: A retrospective case series analysis was done on patients with inflammatory bowel disease (IBD) who were on azathioprine at Leicester General Hospital.

Methods: 111 patients (47 males, 64 females, mean age 35.3 years) were included from gastroenterology outpatients records between November 1997 and August 1998. Clinical and demographic details were collected. Response in Crohn's disease was determined using the Harvey-Bradshaw index. In case of ulcerative colitis the following parameters were used: stool frequency; rectal bleeding, weight gain, and general well-being. Logistic regression was performed to look at the influence of age, sex and diagnosis in relation to the response/relapse rate.

Results: The average duration of treatment with azathioprine was 28.6 months. The starting dose of 1.53 mg/kg was similar to the maintenance dose (1.51 mg/kg). 58 patients had Crohn's disease and 53 patients were diagnosed with ulcerative colitis. 85 patients were steroid-dependent, 9 steroid-resistant, and 17 patients were started on azathioprine on the basis of extensive disease either seen at the time of endoscopy or radiologically. Improvement in clinical features at 3, 6 and 12 months was 69.5, 77 and 84.1%, respectively. 74% patients showed an improvement in relapse rates during the first year on azathioprine compared to 1 year prior to treatment. 68% patients who had shown improvement at 1 year were no longer taking steroids (p = 0.002). Logistic regression did not show any statistically significant influence of age, sex or diagnosis on response. 4.5% patients had leukopenia requiring dose reductions. Severe leukopenia (leukocyte count <2.5 x 10(9)/l) occurred in 3.6% patients.

Conclusions: Response rates in our IBD patients on azathioprine are comparable with those of the published data despite using a relatively smaller dose.