Predictive value of neutrophil-to-lymphocyte ratio in severe pulmonary infection: sex-specific cut-off values needed.

To assess the predictive value of the neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio, and systemic immune inflammation index in severe post-operative pulmonary infection in haemorrhagic stroke patients based on sex.This retrospective study included 193 male and 129 female patients with haemorrhagic stroke and post-operative pulmonary infection. Univariate and multivariate logistic regression models were used to determine the association between inflammatory markers from peripheral blood counts and severe pulmonary infection in these patients.The proportions of severe pulmonary infections in male and female patients were respectively 35.8% and 24.8%, with a significant difference. Among female haemorrhagic stroke patients, the results of the multivariate logistic regression model showed that the NLR on the third post-operative day (≥9.17) was associated with severe pulmonary infection. Among male haemorrhagic stroke patients, the results of the multivariate logistic regression model showed that NLR on the first post-operative day (≥13.28) and NLR on the third post-operative day (≥8.85) were associated with severe pulmonary infection.The predictive values of NLR for post-operative severe pulmonary infection varied among haemorrhagic stroke patients of different sexes. However, a higher NLR on the third post-operative day was associated with severe pulmonary infection in both male and female patients with haemorrhagic stroke..