External validation of the Oakland score to assess safe hospital discharge among adult patients with acute lower gastrointestinal bleeding in an accident and emergency department in Hong Kong

Objective: To externally validate the use of the Oakland score in identification of low-risk lower gastrointestinal bleeding patients who can be safely managed without hospitalisation in an accident and emergency department in Hong Kong. Methods: This single-centre retrospective cohort study included adult patients who attended the accident and emergency department for lower gastrointestinal bleeding and were subsequently admitted to hospital from 1 January 2020 to 31 December 2020. Safe discharge was defined as absence of all of the following adverse outcomes after hospital presentation: blood transfusion; therapeutic colonoscopy, mesenteric embolisation, or laparotomy for bleeding; in-hospital death (all causes); and readmission with subsequent lower gastrointestinal bleeding within 28 days. The sensitivities, specificities and area under the receiver-operating characteristic curve of the Oakland score were calculated. Results: Among 376 patients who were included in this study, 114 (30.3%) of them experienced one or more adverse outcomes. The area under the receiver-operating characteristic curve for safe discharge was 0.88 (95% confidence interval, 0.84-0.91). Using an Oakland score threshold of ⩽8 points as in the original derivation study can achieve 100% sensitivity (95% confidence interval, 96.8%-100%) and 7.3% specificity (95% confidence interval, 4.4%-11.1%) for safe discharge. When the Oakland score threshold was extended to ⩽11 points, a much greater proportion of low-risk patients could be identified, with 97.4% sensitivity (95% confidence interval, 92.5%-99.5%) and 32.8% specificity (95% confidence interval, 27.2%-38.9%) for safe discharge. Conclusion: The Oakland score performed well in identification of lower gastrointestinal bleeding patients who were at low risk of experiencing adverse outcomes and could thus be safely managed without hospitalisation. Extension of the Oakland score threshold to ⩽11 points can allow identification of a greater proportion of low-risk patients while sensitivity is reasonably maintained.