Neutrophil Lymphocyte Ratio and Clinical Outcome in Children Admitted to PICU: A Prospective Observational Study.

Objectives: To evaluate the association of neutrophil-lymphocyte ratio (NLR) with severity of illness and clinical outcomes in critically-ill children.

Methods: Consecutive children (n = 250) aged 1 mo-12 y in PICU were enrolled during Feb-Sep 2021. They underwent blood counts on day-1, day-4, and day-7. Primary outcome was to determine association of NLR with new or progressive multiorgan dysfunction syndrome (NPMODS) and unfavourable outcome (death/discontinuation of care).

Results: Median (IQR) age was 42 (11, 92) mo. Two-thirds (n = 156, 62%) had MODS at admission and 43 (17.2%) developed NPMODS within 7 d. Unfavourable outcome was seen in 44 (17.6%) children. Day-1 NLR was not different in children with or without NPMODS [2.5 (1.7, 6.0) vs. 2.8 (1.5, 5.7); p = 0.63] and in children with or without unfavourable outcome [3.7 (1.7, 7.1) vs. 2.6 (1.5, 5.3); p = 0.16]. However, NLR on day-4 was significantly higher in children with unfavourable outcome [2.6 (1.9, 5.1) vs. 1.9 (1.1, 3.5); p = 0.002]. On ROC analysis, the optimal cutoff of day-4 NLR was 2.02 for predicting unfavourable outcome [AUC 0.65, sensitivity 73%, specificity 52%]. In sepsis subgroup, high NLR was seen in children with unfavourable outcome both on day-1 [3.5 (1.7, 6.7) vs. 2.3 (1.2, 3.8); p = 0.01] and day-4 [2.5 (1.8, 5.6) vs. 1.6 (1, 3.1); p < 0.001].

Conclusions: In critically-ill children, day-1 NLR has no association with organ dysfunction or hospital outcome. However, NLR on day-4 was significantly higher in children with unfavourable outcome, hence monitoring the trend may be useful.