Association between lactate dehydrogenase and the risk of venous thromboembolism and mortality in critically ill patients: a retrospective cohort study

<title>Abstract</title> <p>Venous thromboembolism (VTE) is a leading preventable cause of death in critically ill patients, but early risk stratification remains challenging. Lactate dehydrogenase (LDH) reflects tissue injury and has been linked to thrombosis and poor outcomes in specific diseases, yet its independent role in the general intensive care unit (ICU) population is unclear. This cohort study used data from MIMIC-IV v3.0. We included adults with first ICU stay ≥24h, no VTE on admission, and LDH within 24h. Of 15,999 patients, baseline LDH stratified into quartiles. Primary outcome: incident VTE; secondary: hospital and ICU mortality. Logistic/Cox regression, splines, and Kaplan-Meier analyses with covariate adjustments were applied. Compared with lowest LDH quartile (Q1, &lt;209 IU/L), highest (Q4, ≥461 IU/L) had increased VTE risk after full adjustment (OR 1.35, 95% CI 1.06–1.73; P&lt;0.001). Elevated LDH also predicted higher mortality: for Q4 vs Q1, HRs were 1.74 (1.52–2.00) for hospital and 1.73 (1.45–2.05) for ICU mortality (both P&lt;0.001). Survival declined across quartiles (log-rank P&lt;0.001). Elevated serum LDH is independently associated with increased VTE risk and higher hospital and ICU mortality in critically ill patients. LDH may serve as a practical biomarker for early risk stratification in this population.</p>