P362 Six-year efficacy and safety of azathioprine treatment in the maintenance of steroid-free remission in inflammatory bowel disease patients

Azathioprine (AZA) and thiopurine are widely used for induction and maintenance of remission in patients steroid-resistant or dependent with inflammatory bowel disease (IBD). The treatment must be withdrawn in 5–30% of patients due to the occurrence of adverse events. Aim of this study has been to investigate its efficacy and safety in maintaining steroid-free remission in steroid dependent IBD patients six year after the institution of treatment. Data from consecutive IBD outpatients referred in our Institution, between 1985–2015, were reviewed and all patients treated with AZA were included in this retrospective study. AZA was administered at the recommended dose of 2–2.5 mg/kg. Out of 2722 consecutive IBD outpatients visited in the index period, AZA was prescribed to 415 patients, 227 (54.7%) were affected by Crohn’s disease (CD) and 188 (45.3%) by ulcerative colitis (UC). One hundred and fifty-eight patients with a follow-up <72 months were excluded from the study. Two hundred and fifty-seven patients were evaluated, 143 (55.6%) with CD and 114 (44.4%) with UC. One hundred and forty-two (55.2%) were male and 115 (44.8%) female (average age of 35.68 ± 14.22 SD years, range 14–74 y.). Six year after the institution of treatment, 130 (50.6 %) patients still were in steroid-free remission (85 CD vs. 45 UC, 59.5% and 39.5%, respectively, p = 0.0017), 71 (27.6%) had a relapse requiring retreatment with steroids (29 CD vs. 42 UC, 20.3% and 36.8%, respectively, p = 0.0048), 56 (21.8%) discontinued the treatment due to side effects (29 CD vs. 27 UC, 20.2% and 23.7%, respectively). Loss of response from first to sixth year of follow-up was low, about 20%. Six year after the onset of treatment 50.6% of patients did not require further steroid courses. After the first year loss of response was low in 5 subsequent years. In the present series, the maintenance of steroid-free remission was significantly higher in CD than in UC patients. The occurrence of side effects leading to the withdrawal of AZA treatment has been low.