Association between lactate dehydrogenase and ventilator-associated pneumonia risk: an analysis of the MIMIC database 2001-2019

Serum lactate dehydrogenase (LDH) is a nonspecific inflammatory biomarker and has been reported to be associated with pneumonia prognosis. This study aimed to evaluate the relationship between LDH levels and ventilator-associated pneumonia (VAP) risk in intensive care unit (ICU) patients. This retrospective cohort study used data from the Multiparameter Intelligent Monitoring in Intensive Care database from 2001 to 2019. ICU patients aged ≥ 18 years and receiving mechanical ventilation were included. LDH levels were analyzed as continuous and categorical variables ( 390 IU/L), respectively. Restricted cubic spline (RCS) curves and quartiles were used to categorize LDH levels. Logistic regression and linear regression were utilized to assess the relationship of LDH levels with VAP risk and duration of mechanical ventilation, respectively. A total of 9,164 patients were enrolled, of which 646 (7.05%) patients developed VAP. High levels of LDH increased the risk of VAP [odds ratio (OR) = 1.15, 95% confidence interval (CI): 1.06-1.24] and LDH levels were positively correlated with the duration of mechanical ventilation [β = 4.49, 95%CI: (3.42, 5.56)]. Moreover, patients with LDH levels of 279-390 IU/L (OR = 1.38, 95%CI: 1.08-1.76) and > 390 IU/L (OR = 1.50, 95%CI: 1.18-1.90) had a higher risk of VAP than patients with LDH levels 390 IU/L [β = 11.22, 95%CI: (8.21, 14.22)] (vs.