Background: Ulcerative colitis (UC) is a relapsing gastrointestinal disease. Identifying patients at high risk of UC relapse and initiating preventive treatment can reduce the risk of UC recurrence and its dangerous side effects. The present study was performed to design and pilot-test an online calculation tool for relapse risk prediction in UC.

Methods: This study is based on our previous prospective study on 157 in-remission UC patients. We designed an online website rooted in our pre-developed equation for calculating relapse risk scores. Then, 280 UC patients who were not in relapse were randomly selected from our database, and required information was filled in on the website, accordingly. Finally, the indicators were manually calculated using the formula and compared with online-calculated data.

Results: The developed bilingual website is available at http://www.ucrelapserisk.com. Of 280 UC patients, 151 (53.9%) were male, and the mean age of the total participants was 44.6 years. The median (interquartile range) of the UC relapse risk score and probability of relapse in one year was 5.00 (3-7) and 70% (23-95%), respectively. Thirty-five percent of patients were at high risk of relapse in the following year. There were no differences between the manually and online calculated Seo index, UC risk score, and probability of relapse in one year.

Conclusion: This online tool is now available for patients and clinicians and provides an accurate relapse risk prediction for UC patients.