A Phase Angle Used as a Screening Tool for Malnutrition in Japanese Patients with Liver Cirrhosis

Objective Malnutrition and sarcopenia are associated with poor clinical outcomes in patients with cirrhosis. While the Phase angle (PhA) is a promising marker, validated ethnicity-specific cutoff values for Asian populations, who often show different body composition profiles, are lacking. This study aimed to establish and validate PhA cutoff values for diagnosing malnutrition and sarcopenia in a Japanese cohort. Methods We retrospectively analyzed 337 Japanese patients with liver cirrhosis who were randomly assigned to training (n=235) and validation (n=102) groups. Optimal sex-specific PhA cutoff values were then determined to identify malnutrition and sarcopenia. Overall survival was compared to assess the prognostic value of PhA. Results PhA was positively correlated with the body mass index, albumin level, and other nutritional indices (all p<0.05). A lower PhA was associated with a poorer hepatic reserve, as indicated by the Child-Pugh and mALBI grades (p<0.001). A multivariate analysis identified the PhA as an independent predictor of malnutrition and sarcopenia (p<0.01). Patients in the low PhA group had a shorter overall survival (p=0.024). The optimal PhA cut-off values for malnutrition and sarcopenia were 4.8 for males and 4.2 for females (AUROCs:0.70-0.76). In the validation cohort, the PhA cutoff values showed good sensitivity (76.7%) and a negative predictive value (75.0%) for malnutrition. Conclusion We established and validated the first sex-specific PhA cutoff values for malnutrition in Japanese patients with cirrhosis, which were lower than those in Western populations. PhA independently predicts malnutrition, sarcopenia, and overall survival, thereby offering clinicians a simple, noninvasive screening tool to enhance nutritional assessment in routine practice.