P1068 Limited long-term efficacy of corticosteroids in microscopic colitis emphasizing the need for advanced therapies

Abstract

Abstract Background Microscopic colitis (MC) is a chronic inflammatory bowel disease, characterized by chronic watery diarrhea, and consisting of 2 subtypes: collagenous (CC) and lymphocytic (LC) colitis. It mainly affects middle-aged adults, although it can occur at any age. The only approved therapy is budesonide, preferably administered in a tapering regimen given the high relapse rates. However, little is known about the long-term natural history of the disease. Methods All adult patients diagnosed with MC after clinical and histological assessment at our referral center between 2014 and 2022 were reviewed. Patients with follow-up less than 3 months or in whom no clear description of initiated therapy could be identified by retrospective chart review, were excluded for evaluation of long-term outcomes. Clinical remission was defined according to the Hjortswang criteria as < 3 stools/day or < 1 watery stool/day. Data on relapse rates, subsequent therapies and surgery were collected. Results Three-hundred twenty-four patients were included, of whom 198 (CC 38.3%, LC 61.7%) were eligible for long-term assessment (Table 1) with a median follow-up of 3.7 [1.1 – 6.3] years. Median age at diagnosis was 63.4 [51.6-74.7] years. Concomitant diseases occurring in 3% or more included thyroid dysfunction (11.6%), coeliac disease (3.5%) and Parkinson’s disease (5.1%), which numerically was more prevalent in the LC (7.4%) than CC (1.3%) population (p=0.09). A minority of patients had a family predisposition of IBD (5.6%). Spontaneous clinical remission occurred in 37 (18.6%) patients, while 4 (2.0%) patients were treated with 5ASA. Most patients (79.3%) were treated with corticosteroids, resulting in 81.1% clinical remission within 3 months. Eighty-six patients (54.8%) flared upon steroid tapering and/or withdrawal requiring corticotherapy reinitiation, prolongation or dose intensification. Due to steroid resistance or dependency, subsequent treatment options included 5ASA (n=14), cholestyramine (n=11), methotrexate (n=6) and azathioprine (n=8), all with limited effect. More advanced therapies are being used, including anti-TNF agents (n=25), vedolizumab (n=9) and JAK inhibitors (n=8). Eighteen patients (9.2%) are currently on maintenance advanced therapies for MC. Two treatment-refractory patients underwent colectomy. Conclusion In this large single-center retrospective analysis, steroids confirmed their first line position to induce clinical remission in MC. However, more than 50% of patients relapsed upon steroid tapering and/or withdrawal, resulting in a substantial need for advanced therapy in this patient population. The long-term efficacy and safety of these advanced IBD therapies in MC should therefore be further investigated.