A nomogram based on clinical factors to predict calendar year readmission in patients with ulcerative colitis

BACKGROUND: Readmission shortly after discharge is indicative of an increased disease severity for patients with ulcerative colitis (UC) and ineffectiveness to medical therapy, which may contribute to a dismal prognosis. OBJECTIVES: This study aimed to explore prognostic variables with a nomogram to predict unplanned UC-related readmission within 1 year after discharge. DESIGN: A retrospective cohort study. METHODS: Electronic medical records of all UC patients treated at our center between 1 January 2014 and 31 June 2021 were reviewed. A comprehensive analysis of various characteristics, such as demographics, comorbidities, medical history, follow-up appointments, admission endoscopy, histopathologic features, etc., was used to determine the primary end point, which was unplanned UC-related calendar year readmission. RESULTS: We found that the unplanned UC-related readmission rate within 1 year was 20.8%. In multivariable cox analysis, the predictors of the Elixhauser comorbidity index [Hazard ratio (HR): 3.50, 95% confidence interval (CI): 1.93–6.37], regular follow-up (HR: 0.29, 95% CI: 0.16–0.53), any history of corticosteroid use (HR: 3.38, 95% CI: 1.83–6.27), seral level of C-reactive protein (HR: 1.01, 95% CI: 1.00–1.02), and the UC endoscopic index of severity (HR: 1.29, 95% CI: 1.05–1.57) independently predicted calendar year readmission after discharge. The established nomogram had a consistently high accuracy in predicting calendar year readmission in the training cohort, with a concordance index of 0.784, 0.825, and 0.837 at 13, 26, and 52 weeks, respectively, which was validated in both the internal and external validation cohorts. Therefore, UC patients were divided into clinically low-, high-, and extremely high-risk groups for readmission, based on the calculated score of 272.5 and 378. CONCLUSION: The established nomogram showed good discrimination and calibration powers in predicting calendar year readmission in high-risk UC patients, who may need intensive treatment and regular outpatient visits.