Incremental Value of Platelet-to-Hemoglobin Ratio beyond the R-Baux Score in Predicting Burn Mortality: Evidence from the Recovery Phase

Abstract

Introduction: Burn injuries trigger a systemic inflammatory response that increases mortality risk. The Revised Baux (R-Baux) score, a validated predictor of mortality at the time of admission, is determined by age, burn surface area, and the presence of inhalation injury. Nonetheless, it remains uncertain whether inflammatory indices derived from routine complete blood counts offer additional predictive value beyond this score.

Methods: This retrospective cohort study examined 238 burn patients admitted to a referral hospital in Surabaya, Indonesia, during the period from 2023 to 2024. Four inflammatory ratios derived from complete blood counts were assessed at three distinct phases of the clinical course: the initial phase (24-48 hours), the hyperinflammatory phase (3-7 days), and the recovery phase (beyond 7 days). For each phase, logistic regression models incorporating the R-Baux score alone were compared with each ratio using the likelihood-ratio test and a statistical test for comparing correlated receiver operating characteristic (ROC) curves.

Results: The overall mortality rate was 30.7%. The R-Baux score was a strong predictor of mortality on its own. Upon admission, none of the four ratios enhanced the predictive capability beyond that of the R-Baux score. During the hyperinflammatory phase, both the platelet-to-hemoglobin ratio (PHR) and neutrophil-to-lymphocyte ratio (NLR) contributed modestly yet significantly to prediction. In contrast, during the recovery phase, the PHR provided substantial incremental value, enhancing discrimination from good to excellent. The other ratios did not contribute value in any phase.

Conclusion: Inflammatory indices derived from complete blood count do not significantly surpass the R-Baux score at the time of admission. However, the PHR offers clinically valuable prognostic information, especially during the recovery phase of the clinical course