Predicting the Individual Risk of Acute Severe Colitis at Diagnosis.
Cesarini M., Collins GS., Rönnblom A., Santos A., Wang LM., Sjöberg D., Parkes M., Keshav S., Travis SP.
Acute severe colitis (ASC) is associated with major morbidity. We aimed to develop and externally validate an index that predicted ASC within three years of diagnosis.The development cohort included patients aged 16-89 years, diagnosed with UC in Oxford and followed for three years. Primary outcome was hospitalisation for ASC, excluding patients admitted within one month of diagnosis. Multivariable logistic regression examined the adjusted association of 7 risk factors with ASC. Backwards elimination produced a parsimonious model that was simplified to create an easy-to-use index. External validation occurred in separate cohorts from Cambridge, UK and Uppsala, Sweden.The development cohort (Oxford) included 34/111 patients who developed ASC within a median 14 months (range 1-29). The final model applied the sum of 1 point each for extensive disease, CRP >10mg/L, or haemoglobin <12g/dL F or <14g/dL M at diagnosis, to give a score from 0/3 to 3/3. This predicted a 70% risk of developing ASC within 3y (score 3/3). Validation cohorts included different proportions with ASC (Cambridge=25/96; Uppsala=18/298). Of those scoring 3/3 at diagnosis, 18/18 (Cambridge) and 12/13 (Uppsala) subsequently developed ASC. Discriminant ability (c-index, where 1.0=perfect discrimination) was 0.81 (Oxford), 0.95 (Cambridge), 0.97 (Uppsala). Internal validation using bootstrapping showed good calibration, with similar predicted risk across all cohorts. A nomogram predicted individual risk.An index applied at diagnosis reliably predicts the risk of ASC within three years in different populations. Patients with a score 3/3 at diagnosis may merit early immunomodulator therapy.