Background: Modified Early Warning Systems (MEWS) scores offer proxies for morbidity and mortality, and are easily acquired by any healthcare provider. Composite scores >5 on hospital admission have been validated internally as associated with death and ICU admission. Changes in MEWS scores (delta MEWS) from ED to hospital have been studied, but the significance of changing scores within the ED remains poorly understood. Accordingly, we sought to examine the correlations between ED delta MEWS scores and in-hospital morbidity, mortality and length of stay (LOS).
Methods: We performed a retrospective analysis on ED patients admitted to our institution between November 2017 and November 2018. To exclude scores clearly associated with trauma, physical injury or burns, we excluded patients admitted to the Trauma, Orthopedics or Burn services. Triage-to-Last delta MEWS (LdMEWS) score and Triage-to-Max delta MEWS (MdMEWS) were calculated among all scores obtained in the ED. Each score was correlated using parametric analysis to in-hospital mortality, ICU admission and LOS, after adjusting for sex, age, Charlson Comorbidity Indexes, and triage MEWS score.
Results: Analysis included 8,171 ED patients, with an ICU admission rate of 17.3% and mortality rate of 2%. Using multivariate adjusted regression models, every point improvement in patients’ LdMEWS score in the ED was associated with a reduction in all-cause mortality (OR 0.63, 95% CI 0.57 – 0.70), and in ICU admission (OR 0.68, 95% CI 0.65 – 0.71). Additionally, for every point increase in ED MEWS score after triage (MdMEWS), odds of mortality increased by 1.43 (95% CI 1.27 – 1.61), and ICU admission by 1.46 (95% CI 1.39 – 1.54). For survivors, every point improvement in LdMEWS score in the ED was associated with a 39% RR decrease in hospital LOS (95% CI -0.48 to -0.30), and every point increase in MdMEWS with a 31% RR increase in LOS (95% CI -0.22 to -0.41).
Conclusion: Utilizing MEWS as proxy for a patient’s morbidity and mortality upon presentation to the ED, we are beginning to examine the utility of changing ED MEWS scores during resuscitation. In this cohort, patients with improving ED MEWS scores (LdMEWS) had a lower likelihood of in-hospital mortality, LOS and ICU admission, and every increase in MEWS score after triage (MdMEWS) was associated with increased mortality, LOS and ICU admission.