Steroid Saving Efficacy of Azathioprine: A Nationwide Retrospective Cohort from the Veterans Affairs Healthcare System

Abstract

Purpose: The need for maintenance steroids is associated with a poor prognosis among patient with ulcerative colitis (UC). There is paucity of data regarding the efficacy of azathiopurine (AZA) in maintaining corticosteroids (CS) free remission in UC. Our aim was to assess the ability of AZA to induce CS free remission among UC patients. Methods: A retrospective cohort study was conducted using the nationwide Veterans Affairs (VA) database to identify CS dependent UC patients on AZA from October 1, 2001 to October 1, 2011 using ICD-9 codes. Patients using steroids for greater than 50% of the days in the 3 months leading up to the index AZA dose were considered as CS dependent and were included to our study. Patients were followed for 15 months after the index AZA dispense by tracking their pharmacy dispensing data for prednisone, AZA and infliximab. End points were: 1) successful remission, defined as cessation of prednisone filling activity within the study period while maintained on AZA. 2) Failure with continuance, defined as failure to be weaned off steroids while on AZA. 3) Failure with discontinuance, defined as cessation of AZA and continuation of steroids. Results: We included 548 patients (mean age 52, 92 % males, 79% Caucasian) in our analysis. At the end of 12th month of follow-up 240 (44%) UC patients had achieved successful remission, 79 (14%) failed to achieve remission with continuance of AZA, 229 (42%) failed to achieve remission with discontinuance of AZA, Figure 1. Although, 56% of the study population continued CS therapy through the end of the observation period, the average daily dose of prednisone among patients who were concomitantly taking AZA was 16 mg/day compared to 25 mg/day among those who had stopped AZA, p=0.01. Twelve patients (2%) were placed on infliximab during the follow-up period.Figure: No Caption available.Conclusion: This large nationwide UC patient cohort demonstrated that AZA was successful in attaining CS free remission in almost half of the patients. For those who did not achieve CS free status, CS daily dose was significantly reduced when comparing those who continued AZA versus those who discontinued it. When starting UC patients on steroids, AZA should be considered as a long term steroid sparing option.