Validity of simple mucosal biopsy criteria combined with endoscopy predicting patients with ulcerative colitis ultimately requiring surgery: a multicenter study.

Background: Recent mucosal biopsy criteria combined with endoscopy effectively differentiate patients with ulcerative colitis ultimately requiring surgery (UC-S) from those receiving medication alone (UC-M). However, the criteria were inconvenient in practical use because of the need for complicated calculations, and the validity has not been verified in other institutes where the indications for surgery may differ. The aims of this multicenter study were to propose simple criteria in which calculation can be performed by mental arithmetic and to measure their validity. Methods: Based on the above original criteria, we constructed simple criteria in which coefficients and constant were simplified to integral numbers. The criteria consisted of the diagnostic categories, highest-risk, high-risk, unpredictable, low-risk, and lowest-risk of surgery. The validity of these proposed criteria was evaluated in 121 patients with UC-S and 186 with UC-M from 11 institutes. Results: The categories of high-risk and low-risk had sensitivities exceeding 86.0% and specificities exceeding 95.2%, and the validities were maintained at high levels in most individual institutes. There was little difference in validity between the proposed and original criteria when testing using the same patients. Conclusions: Despite simplified coefficients and constant, the proposed criteria reliably predicted the eventual clinical outcome of patients with ulcerative colitis and would be helpful in determining the necessity of surgery.