Prevalence and Outcomes of No Treatment Versus 5-ASA in Ulcerative Colitis: A Nationwide Analysis From the epi-IIRN

Background Data regarding patients with ulcerative colitis (UC) not receiving maintenance treatment are scarce. In this nationwide study, we aimed to explore the frequency and long-term outcomes of untreated patients with UC vs treated patients. Methods We retrieved data from Israel's Health Maintenance Organizations, covering 98% of the population. No maintenance treatment (NMT) was defined as lack of treatment during the period from 3 to 6 months from diagnosis, allowing at most 3 months for induction treatment. Results A total of 15 111 patients have been diagnosed with UC since 2005, of whom 4410 (29%) have had NMT, with 36 794 person-years of follow-up. NMT was more likely in adults (31%) and in elderly-onset UC (29%) than in pediatric-onset UC (20%; P < .001) and decreased from 38% in 2005 to 18% in 2019 (P < .001). The probability of remaining without treatment was 78%, 49%, and 37% after 1, 3, and 5 years from diagnosis, respectively. In propensity score-matched analysis of 1080 pairs of treated (93% with 5-aminosalicylic acid) and untreated patients, outcomes were comparable for time to biologics (P = .6), surgery (P = .8), steroid dependency (P = .09), and hospitalizations (P = .2). Multivariable modeling indicated that failing NMT was less likely in adults or elderly-onset patients who received at most rectal therapy or antibiotics as induction therapy. Conclusions Nowadays, 18% of patients with UC do not receive maintenance therapy, of whom half remain without treatment after 3 years. Matched pairs of patients on NMT and 5-aminosalicylic acid, representing the mildest patients of the latter, had similar outcomes. Prospective studies are needed to further explore the role of NMT in UC. Lay Summary The rate of no maintenance treatment (NMT) decreased in the last years, but in a propensity score-matched analysis, 5-aminosalicylic acid monotherapy did not demonstrate any therapeutic advantage over NMT. NMT seems to be a viable option in a subset of patients with mild ulcerative colitis.