Development and External Validation of the International Early Warning Score for Improved Age- and Sex-Adjusted In-Hospital Mortality Prediction in the Emergency Department

OBJECTIVES

Early Warning Scores (EWSs) have a great potential to assist clinical decision-making in the emergency department (ED). However, many EWS contain methodological weaknesses in development and validation and have poor predictive performance in older patients. The aim of this study was to develop and externally validate an International Early Warning Score (IEWS) based on a recalibrated National Early warning Score (NEWS) model including age and sex and evaluate its performance independently at arrival to the ED in three age categories (18-65, 66-80, > 80 yr).

DESIGN

International multicenter cohort study.

SETTING

Data was used from three Dutch EDs. External validation was performed in two EDs in Denmark.

PATIENTS

All consecutive ED patients greater than or equal to 18 years in the Netherlands Emergency department Evaluation Database (NEED) with at least two registered vital signs were included, resulting in 95,553 patients. For external validation, 14,809 patients were included from a Danish Multicenter Cohort (DMC).

MEASUREMENTS AND MAIN RESULTS

Model performance to predict in-hospital mortality was evaluated by discrimination, calibration curves and summary statistics, reclassification, and clinical usefulness by decision curve analysis. In-hospital mortality rate was 2.4% ( n = 2,314) in the NEED and 2.5% ( n = 365) in the DMC. Overall, the IEWS performed significantly better than NEWS with an area under the receiving operating characteristic of 0.89 (95% CIs, 0.89-0.90) versus 0.82 (0.82-0.83) in the NEED and 0.87 (0.85-0.88) versus 0.82 (0.80-0.84) at external validation. Calibration for NEWS predictions underestimated risk in older patients and overestimated risk in the youngest, while calibration improved for IEWS with a substantial reclassification of patients from low to high risk and a standardized net benefit of 5-15% in the relevant risk range for all age categories.

CONCLUSIONS

The IEWS substantially improves in-hospital mortality prediction for all ED patients greater than or equal to18 years.

GP cooperative and emergency department: an exploration of patient flows

RATIONALE, AIMS AND OBJECTIVES

In most countries, different health care providers are involved in emergency care. In the Netherlands, out-of-hours care is provided by general practitioner cooperatives (GPCs) and emergency departments (EDs). Our aim was to describe the flow of patients attending emergency care in these settings.

METHOD

A retrospective record review was performed, concerning patients who had visited a GPC or ED. Recorded information included urgency, diagnostic tests, and follow-up contacts. Descriptive figures were determined for patient flows in GPC and ED for urgent contacts and non-urgent contacts.

RESULTS

We included 319 GPC contacts and 356 ED contacts, of which 78% were non-urgent. The majority of GPC contacts were completed at the GPC without follow-up; 37% of non-urgent patients had a follow-up contact, usually with primary care. Only 5% of non-urgent GPC patients received diagnostic tests compared to 63% of non-urgent ED patients (mostly X-rays). The majority of non-urgent ED patients (88%) had a follow-up contact, usually at an outpatient clinic (67%). Most non-urgent ED patients (83%) who received a diagnostic test also had an outpatient clinic follow-up contact. Of urgent ED patients, the majority had a follow-up contact (85%), mostly with an outpatient clinic (74%).

CONCLUSION

Although most out-of-hours care patients present non-urgent health problems, at the ED they are more likely to receive diagnostic tests and follow-up contacts. This may reflect differences in patient populations between the ED and GPC or suggest opportunities for improving efficiency of planning follow-up contacts.