Phoenix Sepsis Score as a prognostic tool for mortality in immunocompromised children with sepsis and septic shock: a six-year study from a Thai referral center

Immunocompromised children with sepsis and septic shock face substantially higher mortality rates. This study aimed to evaluate the Phoenix Sepsis Score as a prognostic tool for mortality and to identify factors associated with mortality in immunocompromised children with sepsis and septic shock. A retrospective study was conducted among immunocompromised pediatric patients aged 1 month to 18 years diagnosed with sepsis and septic shock, admitted to the Pediatric Intensive Care Unit (PICU) of Srinagarind Hospital, Khon Kaen University, Thailand, from 2018 to 2023. Sepsis and septic shock were classified using the 2024 Phoenix Sepsis Score criteria. Multivariate analysis was used to analyze factors associated with mortality. Receiver operating characteristic (ROC) curve analysis was performed to evaluate discriminative performance. Of 92 patients, 34 (37%) died. Malignancy was the most common underlying condition (56.5%), and septic shock was present in 76.1%. The maximum Phoenix Sepsis Score (first 24 h) was the strongest independent prognostic factor for mortality (AOR 8.20 per 1-point increase, 95% CI 1.35–49.69, p = 0.022). An exploratory cutoff of ≥ 8 achieved 100% sensitivity and 93.1% specificity. The maximum Phoenix Sepsis Score during the first 24 h demonstrated strong discriminative ability for mortality prediction in immunocompromised children with sepsis and septic shock. An exploratory cutoff of ≥ 8 in this cohort suggests potential utility as a screening threshold for identifying high-risk immunocompromised children, yet requires external validation.