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Published on: June 10, 2025
Bioelectrical Impedance Phase Angle and Morbidity and Mortality in Critically Ill Children
Patrícia Zamberlan1, Rubens Feferbaum2, Ulysses Doria Filho3
1Division of Nutrition, Faculty of Medicine, Hospital das Clinicas Instituto da Crianca, University of São Paulo, São Paulo, Brazil.
Insights
Body composition indicators like mid-upper arm circumference and phase angle can help predict mortality and length of stay in critically ill children. These nutrition markers offer valuable prognostic insights for pediatric intensive care unit patients.
Area of Science:
- Pediatric critical care medicine
- Nutritional assessment in pediatrics
- Biomarkers for critical illness
Background:
- Nutrition markers are vital for diagnosing, monitoring, and predicting mortality risk in critically ill patients.
- Body composition indicators, specifically mid-upper arm circumference and phase angle, were investigated for their prognostic value.
- Assessing nutritional status is crucial for improving outcomes in pediatric intensive care unit (PICU) settings.
Purpose of the Study:
- To determine the association between body composition indicators (mid-upper arm circumference and phase angle) and outcomes in critically ill children.
- To evaluate the utility of these markers in predicting mortality and length of stay in the PICU.
- To establish phase angle as a prognostic indicator in pediatric critical care.
Main Methods:
- A cohort of 247 children (2 months–18 years) admitted to the PICU was studied.
- Phase angle was measured using bioelectrical impedance analysis; severity was assessed using the Pediatric Index of Mortality score.
- Receiver operating characteristic curve analysis and Kaplan-Meier survival analysis were employed to evaluate associations.
Main Results:
- Higher survival rates were observed in children with a phase angle >2.8° compared to those with ≤2.8° (P < .0001).
- Lower phase angle values correlated with a longer PICU length of stay (hazard ratio, 1.84; P = .003).
- Reduced survival was also linked to mid-upper arm circumference values at or below the 5th percentile (P < .03).
Conclusions:
- Mid-upper arm circumference and phase angle are significantly associated with mortality and morbidity in critically ill children.
- These body composition indicators serve as valuable tools for nutritional diagnosis and monitoring.
- Phase angle and mid-upper arm circumference can be utilized as additional prognostic indicators in pediatric critical care settings.
Background:
Nutrition markers may be useful for diagnosis and monitoring and, also, as additional indicators of estimating death risk. We tested the association of body composition indicators (mid-upper arm circumference and phase angle) with pediatric intensive care unit (PICU) length of stay and mortality in critically ill pediatric patients.
Methods:
Data from children aged 2 months-18 years were collected, and bioelectrical impedance was performed to obtain phase angle. Severity was evaluated by scoring the Pediatric Index of Mortality. Descriptive statistics were reported for nominal variables. Receiver operating characteristic curve was used to analyze the association of phase angle with 30-day mortality and to find the best cutoff. Survival probabilities and PICU length of stay were estimated using the Kaplan-Meier method.
Results:
We evaluated 247 children with a median age of 4.8 years whose main cause of admission was sepsis. Survival curves showed higher survival in patients with phase angle >2.8° compared with patients with phase angle ≤2.8° (P < .0001). Kaplan-Meier time-to-event analysis showed that children with lower phase angle values were more likely to remain in the PICU (hazard ratio, 1.84; P = .003). Lower survival was also observed in patients who presented mid-upper arm circumference values ≤5th percentile (P < .03).
Conclusions:
Mid-upper arm circumference and phase angle were associated with mortality and morbidity in critically ill children, suggesting that these parameters may be useful not only for nutrition diagnosis and monitoring, but also as an additional indicator in estimating prognosis.
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