Early Warning Scores to Predict Noncritical Events Overnight in Hospitalized Medical Patients: A Prospective Case Cohort Study

BACKGROUND: Physicians are often called to evaluate patients overnight with varying levels of clinical deterioration. Early warning scores predict critical clinical deterioration in patients; however, it is unknown whether they are able to reliably predict which patients will need to be seen overnight and whether these patients will require further resource use. METHODS: A prospective case cohort study of 522 patient nights in a single tertiary care hospital in Vancouver, British Columbia, Canada, was conducted to assess the ability of Modified Early Warning Score (MEWS) and National Early Warning Score (NEWS) to predict patients who will need to be seen overnight by physicians and will require other healthcare resources. Prediction ability was assessed using area under the receiver operating characteristic curve and logistic regression models. RESULTS: The MEWS and NEWS both significantly predicted which patients needed to be seen overnight, and area under the receiver operating characteristic curves (95% confidence interval) for MEWS and NEWS were 0.72 (0.66-0.78) and 0.69 (0.63-0.76), respectively. Odds ratios (95% confidence interval) for MEWS and NEWS predicting need to be seen overnight were 1.52 (1.34-1.73) and 1.22 (1.14-1.31), respectively. CONCLUSIONS: Both MEWS and NEWS have fair ability to predict patients who will need to be seen overnight. This may be useful for improving handover and resource allocation for overnight care.