Retrospective evaluation of the neutrophil-to-lymphocyte ratio as a prognostic marker in cats with blunt trauma (2018-2021): 177 cases

Objective: To investigate the utility of the neutrophil-to-lymphocyte ratio (NLR) as a prognostic marker in cats with blunt trauma. Design: Retrospective study from January 2018 to December 2021. Setting: University teaching hospital. Animals: Medical records of 177 cats admitted with blunt trauma were evaluated. History, clinical findings, blood cell count-based ratios, thoracic radiographs on presentation, and outcome were reviewed. The Animal Trauma Triage (ATT) score was assessed in each cat and classified as mild (1-3), moderate (4-7), and severe trauma (>= 8). Forty-eight healthy blood donor cats served as the control population. NLR, neutrophil counts, and lymphocyte counts were compared between cats with blunt trauma and controls, and among trauma patients. Interventions: None Measurements and Main Results: NLR, neutrophil counts, and lymphocyte counts significantly differ in cats with blunt trauma compared to controls (p < 0.001), and NLR was higher in patients with thoracic trauma (p = 0.044). Nonsurvivors had lower lymphocyte counts (p = 0.041), although those values do not appear to be clinically relevant. A significant increase in NLR was observed with increasing severity of trauma (p < 0.001). The NLR was not associated with the length of hospitalization, intensive care assistance, or mortality. Conclusion: NLR is a widely available diagnostic tool, which can be used in addition to ATT to assess trauma severity, although in our study it was not predictive of the outcome.