Neutrophil-to-Lymphocyte Ratio Associations with Nosocomial Infections and Non-neurologic Organ Dysfunction in Moderate-to-Severe Traumatic Brain Injuries

Traumatic brain injuries (TBI) represent an immense public health encumbrance carrying high rates of mortality and chronic disability which leaves a severe cost burden on patient families. Establishing cost-effective, objective, and readily available biomarkers like neutrophil-to-lymphocyte ratios (NLR), is imperative for clinical prognostication in TBI patients. No TBI-specific studies have explored how NLR is affected by systemic secondary events, Non-neurologic organ dysfunction (NNOD) or infections. This study uncovered the prevalence of NNOD and infection and established significant relationships between infections, NNOD and NLR in a moderate-to-severe TBI population. Using multivariable logistic regression, we then explored and discovered significant relationships between early NNOD and infection development and increased levels of later NLR. Finally, we explored how all three of these factors were associated with six-month outcome and found that all three factors, NNOD, infections and NLR, were associated with unfavorable six-month outcome. This study sets the stage for future, hypothesis-driven studies investigating temporal dynamics of cellular immune responses and the causality of infections and NNOD.