Use of the neutrophil - to - lymphocyte ratio improves the accuracy of outcome prediction in patients with acute traumatic subdural hematoma undergoing surgical treatment

Introduction: Traumatic brain injury (TBI) is a major cause of disability and mortality worldwide. Acute traumatic subdural hematoma (TSDH) accounts for a large proportion of all TBI cases. However, factors to predict postoperative prognosis in patients with acute TSDH are limited. Recently, it has been reported that inflammatory markers increase the accuracy of prognosis in various diseases. The neutrophil-to-lymphocyte ratio (NLR) is a marker for inflammation, which is easy to test, inexpensive and can be performed quickly. However, the prognostic value of NLR in patients with acute TSDH remains controversial. This study therefore aimed to assess the predictive value of the admission and postoperative NLR in patients with acute TSDH who underwent surgical treatment.

Methods: We retrospectively identified patients who were underwent surgery for acute TSDH at our institute between April 2010 and August 2023. The NLR was calculated as the ratio of the absolute neutrophil count (ANC) to the absolute lymphocyte count (ALC). Multivariable logistic regression analysis was subsequently applied to assess the independent predictors of 30-day mortality. In logistic regression analysis, multivariate analysis was performed using the backward elimination method for all p-value<0.05 in the univariate analysis. Receiver operating characteristic (ROC) curve analysis was used to assess the predictive abilities of the postoperative 48-hour NLR and determine the cutoff values.

Results: A total of 131 patients were enrolled, among whom the mortality within 1 month was 47.3% (62 patients). Initial NLR (p value = 0.905) was not strongly associated with mortality in patients with acute TSDH who underwent surgery. Only the postoperative 48-hour NLR (OR, 1.103; 95% CI, 1.051-1.157; p < 0.001) and Glasgow coma scale score at admission (OR, 0.855; 95% CI, 0.756-0.967; p = 0.012) were independent factors for 1 month mortality in the multivariate logistic analysis. The optimal cut-off value of the postoperative 48-hour NLR to distinguish between survival and non-survival was 15.786.

Conclusion: Initial NLR was not strongly associated with 1-month mortality in patients with acute TSDH who underwent surgery. However, the postoperative 48-hour NLR was associated with 1 month mortality.