Mortality risk scoring in emergency general surgery: Are we using the best tool?

Area of Science:

• Surgical Outcomes Research
• Clinical Risk Stratification
• Emergency Medicine

Background:

• Accurate preoperative risk assessment is crucial for patients undergoing emergency laparotomy.
• The Portsmouth-Physiological and Operative Severity Score for the enumeration of Mortality and Morbidity (P-POSSUM) is a widely used risk assessment tool.
• The National Emergency Laparotomy Audit (NELA) score is a novel, validated alternative, but direct comparison with P-POSSUM is lacking.

Purpose of the Study:

• To compare the predictive accuracy of the NELA score and the P-POSSUM score for mortality in patients undergoing emergency laparotomy.
• To determine which scoring system provides superior discrimination for predicting death.

Main Methods:

• Analysis of 650 patient entries from the NELA online database over 4.5 years.
• Assessment of model calibration using the Hosmer-Lemeshow goodness of fit test.
• Non-parametric receiver operator characteristic (ROC) analysis to evaluate discriminative power for mortality.

Main Results:

• The NELA score exhibited higher discriminative power for mortality (C-index = 0.818) compared to the P-POSSUM score (C-index = 0.769).
• Observed mortality rate was 9.1% (59 deaths).
• P-POSSUM predicted 15.2% mortality, while NELA predicted 7.8% mortality.

Conclusions:

• The NELA score demonstrates good discrimination for predicting mortality in the emergency laparotomy cohort.
• P-POSSUM over-predicted observed mortality, whereas the NELA score under-predicted observed mortality.
• NELA score is a more accurate predictor of mortality in this patient population.