Phase angle (PhA) is a valuable tool for evaluating the nutritional and inflammatory status, which can accompany acute and severe disorders. PhA is a cellular health biomarker, whose value is particularly substantial due to the negative consequences of these situations in the pediatric population. Relevant literature was collected with the aim of comprehensively analysing the evidence on the association between an altered PhA can serve as a predictive-marker for mortality and poor-outcomes in at-risk-pediatric patients. Understanding this relationship could have significant implications for identifying high-risk individuals and implementing timely interventions. A systematic review with meta-analysis was conducted in the primary electronic databases from inception until January 2023. Overall, four studies with a total of 740 patients were eligible for our analysis. Evidence demonstrates that PhA is associated with nutritional status, reflecting undernutrition and changes in body composition related to illness. This review suggests that PhA can indeed be used as an indicator of nutritional status and a tool for predicting prognosis, including mortality and poor-outcomes, in hospitalized pediatric patients. A low PhA was associated with a significant mortality risk [RR:1.51;95%CI (1.22–1.88),p = 0.0002;I2 = 0%,(p = 0.99)] and an increased complications risk [OR:8.17;95%CI (2.44–27.4),p = 0.0007;I2 = 44%,(p = 0.18)]. These findings highlight the importance of taking a comprehensive approach to clinical nutrition, integrating multiple evaluation aspects to establish an accurate diagnosis and personalized therapeutic plans. While PhA emerges as a valuable tool for assessing the risk of malnutrition and as a prognostic-indicator for poor-outcomes in pediatric patients. Further future studies are needed to focus on investigating this relationship in larger and diverse population to strengthen the evidence base.
