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Predicting mortality based on body composition analysis
J M Tellado1, J L Garcia-Sabrido, J A Hanley
1Servicio Cirugia General II, Hospital Gregorio Marañon, Madrid, Spain.
Annals of Surgery
|January 1, 1989
Summary
The Nae/Ke ratio, a measure of exchangeable sodium to potassium, effectively identifies surgical patients at risk of mortality. This nutritional marker proved superior to traditional anthropometric and biochemical assessments in predicting patient outcomes.
Area of Science:
- Nutritional biochemistry
- Surgical patient monitoring
- Biomarker discovery
Background:
- Malnutrition is a significant risk factor for mortality in surgical patients.
- Traditional nutritional markers often lack predictive power for mortality.
- The Nae/Ke ratio's potential as a predictive nutritional marker requires investigation.
Purpose of the Study:
- To evaluate the Nae/Ke ratio as a nutritional marker for identifying surgical patients at risk of mortality.
- To compare the predictive power of the Nae/Ke ratio against anthropometric, biochemical, and immunologic markers.
- To develop and validate a predictive model for hospital mortality based on the Nae/Ke ratio.
Main Methods:
- Multiple isotope dilution was used to determine the Nae/Ke ratio in 73 malnourished surgical patients (Training Group).
- Stepwise discriminant analysis and logistic regression were employed to assess predictive power for hospital mortality.
- The developed model was validated in a separate cohort of 417 surgical patients (Validation Group).
Main Results:
- The Nae/Ke ratio demonstrated exceptionally strong predictive power for mortality (p < 0.00001), surpassing all other assessed variables.
- A logistic regression model (Pr/death/ = 1/(1 + e[11.8-5.2 Nae/Ke])) was developed, identifying Nae/Ke ratios of 1.5 and 2.5 as markers for non-risk and mortality.
- Validation in an independent cohort confirmed the model's accuracy, with observed deaths closely matching expected deaths (X2 = 1.8 NS) and high ROC curve areas (Az ≈ 0.91).
Conclusions:
- The Nae/Ke ratio is a superior method for identifying malnourished surgical patients at risk of dying compared to conventional anthropometric and biochemical measurements.
- The Nae/Ke ratio offers a robust and validated tool for risk stratification in surgical patient populations.
- Availability of the Nae/Ke ratio can significantly improve clinical decision-making and patient management in surgical settings.
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