Mesalazine enteric-coated tablets combined with retention enema for symptom alleviation in mild to moderate E2-type active ulcerative colitis: A retrospective comparative cohort study

Abstract: Background: Ulcerative colitis (UC) is a chronic inflammatory bowel disease impacting quality of life. Combination oral and topical mesalazine is guideline-recommended for left-sided UC, but real-world data remain limited. Objectives: This retrospective study evaluated the efficacy and safety of mesalazine enteric-coated tablets plus a retention enema in patients with mild-to-moderate E2-type (left-sided) active UC. Methods: Patients with mild to moderate E2-type active UC treated at a single center from January 2021 to December 2022 were retrospectively screened. After applying inclusion and exclusion criteria, 88 patients were included and assigned to either the study group (mesalazine enteric-coated tablets 1.0 g four times daily plus mesalazine retention enema 4.0 g once daily) or the control group (oral mesalazine enteric-coated tablets 1.0 g four times daily alone) based on clinical availability and patient preference. Treatment duration was 30 days. Outcomes included clinical efficacy (using modified local criteria and Mayo score components), symptom relief and time to improvement, endoscopic findings (Mayo Endoscopic Subscore), and adverse events. Results: The “effective” rate was significantly higher in the study group (77.27% vs. 34.09%; OR=6.58, P<0.001). Symptom relief rate was 97.73% vs. 72.73% (OR=13.44, P=0.002). Symptom improvement times were shorter in the study group (all P<0.05). Post-treatment Mayo Endoscopic Subscore was lower in the study group (1.14±0.41 vs. 2.05±0.65; mean difference -0.91, P<0.001). Ulcer and congestion/edema incidences were lower in the study group (6.82% and 18.18% vs. 25.00% and 47.73%). Adverse events were mild and comparable between groups (13.64% vs. 11.36%, P=0.746). Conclusion: Mesalazine enteric-coated tablets combined with retention enema demonstrated superior efficacy compared to oral monotherapy for short-term symptom relief and mucosal healing in patients with mild to moderate E2-type active UC, with a favorable safety profile. Larger prospective studies with longer follow-up are needed to confirm these findings and evaluate long-term outcomes.