The phoenix sepsis score for high mortality risk identification and prognostic predict in pediatric liver transplant recipients

To evaluate the performance of Phoenix Sepsis Score (PSS) in pediatric liver transplant (LT) recipients admitted to PICU with suspected or proven infection, and to explore the association between PSS and PICU mortality for risk stratification. We retrospectively enrolled pediatric LT recipients admitted to PICU. PSS threshold of ≥ 2 was applied to assess early identification of patients at high mortality risk compared with the International Pediatric Sepsis Consensus Conference (IPSCC) criteria, while PSS was further evaluated in relation to PICU mortality. Among 132 pediatric liver transplant recipients, 117 (88.6%) developed sepsis. Compared with non-sepsis patients, those with sepsis were younger, had lower body weight, and were admitted to PICU earlier after transplantation. Organ dysfunction was more frequent in sepsis group, whereas the incidence of acute kidney injury did not differ. Overall mortality was 28.8% (38/132) exclusively in patients with sepsis. Using PICU mortality as the reference outcome, PSS-based sepsis and septic shock demonstrated higher sensitivity (100.0%, 95% CI 90.82-100.00; 76.32%, 95% CI 60.79-87.01) and positive predictive value (32.48%, 95% CI 24.67-41.40; 54.72%, 95% CI 41.45-67.34) than IPSCC criteria. PSS showed superior discrimination, with the highest area under the receiver operating characteristic curve (AUROC 0.868; 95% CI 0.802-0.934) and precision-recall curve (AUPRC 0.784; 95% CI 0.656-0.880), outperforming the conventional scores. PICU mortality increased stepwise across higher PSS categories. CONCLUSION: The Phoenix Sepsis criteria achieves superior mortality risk identification over IPSCC criteria and score outperforms conventional scoring systems in predicting PICU mortality, supporting its risk stratification in pediatric liver transplant recipients. WHAT IS KNOWN: • Immunocompromised pediatric liver transplant recipients have higher PICU mortality after sepsis. While the Phoenix Sepsis Criteria has been validated to outperform conventional IPSCC criteria in general critically ill children, its prognostic predictive performance remains unassessed in this high-risk transplant population. WHAT IS NEW: • This study demonstrates that among pediatric liver transplant recipients, an immunocompromised high-risk cohort, the Phoenix Sepsis Criteria is superior to the IPSCC Criteria in identifying PICU mortality risk, and this scoring system exhibits better prognostic predictive performance than conventional scoring tools. • The findings provide evidence to support clinical adoption of the Phoenix Sepsis Score for optimized risk stratification in post-transplant children.