Association between preoperative blood glucose levels and postoperative pneumonia in neurosurgical patients: a retrospective study.

Background: Blood glucose levels are associated with the occurrence of infections. However, the relationship between preoperative blood glucose (POBG) levels in neurosurgery patients and the development of postoperative pneumonia (POP) remains uncertain. This study aimed to evaluate the association between POBG levels and the occurrence of POP in patients undergoing neurosurgery. Methods: A retrospective study enrolled 1,234 patients who had undergone neurosurgery at The Fourth Affiliated Hospital of Soochow University between January 2021 and June 2024 to investigate the association of POBG levels and POP. The endpoint was defined as pneumonia occurring within 30 days after surgery. Multivariate logistic regression analysis was applied to identify the association between POBG and POP. Receiver operating characteristic analysis was performed to evaluate the predictive accuracy, sensitivity, and specificity of POBG levels for the development of POP. Results: Among the 1,234 participants, 122 cases of POP were identified. POBG was positively correlated with the occurrence of POP after controlling for potential confounders [odds ratio (OR) =1.204, 95% confidence interval (CI): 1.114-1.302, P<0.001]. After full adjustment for covariates, the POBG showed a nonlinear relationship with POP, with a threshold of approximately 6.4 mmol/L. The area under the curve for POBG was 80.8% (95% CI: 77.4-84.2%) with an optimal cut-off value of 6.37 mmol/L, resulting in a sensitivity of 65.6% and a specificity of 85.9%. Conclusions: There exists a saturated nonlinear relationship between POBG levels and the occurrence of POP in post-neurosurgery patients. POBG levels correlate with POP risk in neurosurgical patients and offer auxiliary reference information when clinicians formulate preventive plans.