The Effectiveness of Huangkui Lianchang Decoction Enema Solution Compared with Mesalazine Enema for Mild-to-Moderate Active Distal Ulcerative Colitis: Study Protocol of a Multicenter, Prospective, Randomized Controlled Trial.

Introduction: Traditional Chinese medicine enemas have been widely utilized in clinical practice due to their rapid and effective relief of symptoms such as bloody stools and abdominal pain in ulcerative colitis (UC), sustained therapeutic effectiveness, and low cost. The objective of this multicenter, unblinded randomized controlled trial (RCT) is to evaluate whether the effectiveness and safety of HKE are comparable to those of Mesalazine enemas. Evidence from observational studies is of insufficient quality, underscoring the need for randomized controlled trials to strengthen the reliability and validity of the findings. Methods and Analysis: Eight hospitals in Jiangsu Province with Good Clinical Practice (GCP) certification will recruit patients with mild to moderate active rectal or left-sided colonic UC and randomly assign them in a 1:1 ratio to the Huangkui Lianchang decoction Enema (HKE) treatment group and the mesalazine enema treatment group. All participants received oral Mesalazine enteric-coated tablets. Enema treatment is administered for 8 weeks. Eighty-six patients are recruited for each group. Clinical events are monitored throughout the treatment and follow-up periods. The primary outcome is the modified Mayo score, assessed at baseline and post-treatment (on Day 56 ± 7). This score is used to evaluate both clinical outcomes (clinical remission and response rates) and endoscopic outcomes (endoscopic response and mucosal healing rates). Secondary outcomes include improvements in traditional Chinese medicine symptom scores, resolution rates of individual symptoms, endoscopic mucosal healing rates, and changes in C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and fecal calprotectin levels. Discussion: The outcomes of this research aim to provide evidence supporting the efficacy and safety of HKE enemas for treating ulcerative colitis, and generate high-quality evidence on the treatment of UC with Chinese herbal medicine retention enemas through rigorous clinical investigation. The findings are intended to inform the optimization of therapeutic strategies in clinical guidelines. As this study is a protocol, no results are available at this stage. Trial Registration Number: International Traditional Medicine Clinical Trial Registry ITMCTR2024000702 (https://itmctr.ccebtcm.org.cn/mgt/project/view/-7877458543771072185).