External Validation of a Prognostic Risk Score for Safe Discharge Among Patients With Lower Gastrointestinal Bleeding: A Prospective Multi-centre Cohort Study

Of critical importance in the approach to care of these patients is differentiating the majority of people who can be safely discharged for outpatient management from those who are at risk for serious adverse events and require hospitalization. Recently, Oakland and Jairath developed a clinical prediction rule for safe discharge among patients with LGIB using data from their UK National Audit. The next step in the development of a clinical prediction rule is external validation in independent cohorts. Measures of predictive accuracy for risk scores, such as the AUC, are overly optimistic when calculated from the derivation cohort from which the risk score was derived. Therefore, it is essential to evaluate its performance using independent and diverse validation cohorts. Thus, the goal of this study is to perform the first prospective, multi-centered, external validation of the Oakland-Jairath risk score on an independent and diverse population who present to the emergency room with LGIB. This is a prospective multi-centre observational study to externally validate the Oakland-Jairath LGIB risk score, herein referred to simply as the "risk score".

Consecutive patients presenting to hospital over a 6 month period will have their risk score calculated and followed for the development of an adverse outcome over a 28 day period. The risk score will be determined for research purposes only but will be shared with the treating physician if requested as the details of the risk score itself is within the public domain. Patients will be eligible regardless of discharge status and all admission decisions will be made solely by the treating physicians. To increase the diversity of the validation cohort, increase generalizability, and hasten recruitment, the study will be conducted at 4 centres: Western University, University of Alberta, University of Montreal, and McGill University.