Pediatric Early Warning System (PEWS) Association with ICU Mortality in Children with Acute Lymphoblastic Leukemia: A Cohort Study from Kazakhstan.

: Childhood acute lymphoblastic leukemia (ALL) carries substantial morbidity, mortality, and economic burden, particularly in middle-income countries. The Pediatric Early Warning System (PEWS) is designed to trigger timely escalation of care, yet its independent impact on survival among critically ill leukemic children has not been well defined in Kazakhstan and Central Asia. : We conducted a retrospective review all ICU admissions for patients aged 0-18 years with ALL at the National Center of Pediatrics, Almaty, across two periods: pre-implementation (January 2020-December 2022) and post-implementation of 24 h PEWS monitoring (September 2023-December 2024). The primary outcome was ICU mortality. Seven domains of covariates-demographic, clinical history, transfusion, vital signs, symptoms, laboratory, and instrumental data-were extracted. Univariable and multivariable logistic regression models were used to assess associations with mortality. : Among 255 admissions (105 during PEWS implementation; 150 prior to PEWS implementation), overall ICU mortality was 21.7%. After adjustment, PEWS implementation was not associated with reduced ICU mortality (AOR 0.89), despite a lower unadjusted mortality (15.9% vs. 26.6%). The most clinically relevant secondary findings included strong associations between mortality and bilateral pneumonia (AOR 7.45), ≥4 episodes of hyperthermia within 24 h of ICU admission (AOR 5.42), and systemic inflammatory response syndrome (AOR 4.61). : These findings suggest that, within this high-acuity cohort, inflammatory and cardiorespiratory derangements outweigh any potential survival benefit from ward-based PEWS surveillance. Optimizing outcomes will require integrating early warning systems with timely deterioration management, focused cardiopulmonary support, and resource allocation tailored to the clinical context-rather than relying solely on surveillance scores.