Azathioprine is widely in the Asia Pacific region for patients with steroid-resistant and dependent IBD. However, the predictors of efficacy and optimal dosing of Azathioprine (AZA) has not been evaluated in this region. We aimed to investigate the optimal dosing and the predictors of efficacy of AZA in maintaining steroid-free remission in a well defined Indian IBD cohort.Methods
Prospectively collected data of patients on AZA from the IBD registry, at Asian Institute of Gastroenterology, Hyderabad was analysed. The relapse rate, time to relapse and reasons for stopping treatment were included. An age and a sex-matched historical cohort of patients not on AZA were used as a control. Median relapse-free interval was estimated using Kaplan-Meier survival analysis. The impact of treatment with azathioprine on the risk of relapse was assessed using Cox proportional hazards model.Results
396 patients [Mean age 37 years, 59% men, 208 (52%) with CD] on AZA were identified. AZA was effective in preventing relapse in both Crohn’s disease (CD) and Ulcerative colitis (UC) compared to patients not on AZA (p<0.001) (table 1). The mean dose of AZA was 1.48 mg/kg (Range 0.59–3.77). Only 23.2% patients had to discontinue AZA for lack of effectiveness, pregnancy and side effects. Patients with CD on AZA took a longer time to their relapse than with UC on AZA (Log-Rank Test- p=0.072) (figure 1). In the multivariate Cox proportional hazards model, UC patients had 80% higher chance of having a relapse compared to CD patients adjusting other variables (Hazard ratio- 1.8, 95% CI-1.2–2.7, p=0.007).Conclusions
Low dose AZA appears to be a safe and effective drug for maintaining steroid-free remission in Indian IBD patients. AZA is more efficacious in preventing a relapse in CD compared to UC.