High relapse rates after budesonide in microscopic colitis: a large retrospective analysis revealing the need for advanced therapies

Background: Microscopic colitis (MC) is a chronic inflammatory bowel disorder causing watery diarrhea despite normal endoscopic findings. Budesonide is the only approved therapy, yet long-term durability and the need for alternatives in steroid-dependent or -refractory cases remain unclear.

Methods: We performed a retrospective single-center cohort study of all patients with histologically confirmed MC between 2013 and 2022, with ≥3 months of follow-up. Demographics, clinical features, treatments, and outcomes were collected. Clinical remission followed Hjortswang criteria: fewer than three stools per day or fewer than one watery stool per day on average.

Results: A total of 239 idiopathic MC patients met inclusion criteria. Spontaneous remission occurred in 19.2%, more often in males (OR 2.39, p=0.02). Corticosteroids, predominantly budesonide, were prescribed in 78.7% and induced remission in 75.5% within three months. Relapse affected 54.8% of responders, typically during tapering (44.6%) or shortly after cessation (55.3%). Younger age predicted relapse (OR 0.97, p=0.003). Conventional alternatives, including 5-ASA, cholestyramine, methotrexate, and azathioprine, were largely ineffective after corticosteroid failure or dependency. Advanced therapies (anti-TNF agents, vedolizumab, JAK inhibitors) were initiated in 12.6%, more often in younger patients (OR 0.95, p=0.001) and those with a family history of IBD (OR 4.11, p=0.03). These therapies achieved post-induction remission in 70% of refractory cases. Two patients required colectomy.

Conclusion: In this large cohort with long-term follow-up, budesonide remained the primary treatment, yet over half of responders relapsed during tapering or after discontinuation. Conventional alternatives showed limited benefit. Advanced therapies demonstrated meaningful effectiveness in steroid-refractory or steroid-dependent MC, underscoring the need for broader therapeutic options.

Keywords: microscopic colitis, long-term disease course, budesonide, advanced therapy..