BACKGROUND

Infective endocarditis (IE) is a serious infectious disease with a rising incidence rate and high mortality rate. While lactate dehydrogenase (LDH) is a sensitive and accessible biomarker of inflammation, tissue damage and metabolic alteration, its prognostic value in IE remains unexplored.

OBJECTIVE

This study aims to investigate the prognostic value of admission serum LDH levels for 28-day mortality in critically ill IE patients.

METHODS

The data used in this retrospective cohort study was extracted from the MIMIC-IV database. Restricted cubic spline analysis, Cox regression, Kaplan-Meier survival analysis, and receiver operating characteristic analysis were performed to evaluate the predictive value of serum LDH in critically ill IE patients. Key clinical confounders for the adjusting Cox models were filtered by LASSO regression.

RESULTS

A total of 215 critically ill patients with diagnosed IE were included during their first intensive care unit admission. LDH was one of the most significant confounders identified by LASSO analysis. The crude and adjusted Cox models revealed a consistently independent and dose-response relationship between high serum LDH and higher mortality. The fully adjusted model showed each standard deviation increase in LDH (log2) was associated with a hazard ratio of 2.37 (95% CI: 1.51-3.71, p < 0.001). Kaplan-Meier curves demonstrated significantly different survival patterns across LDH levels (p = 0.0032). The area under the curve (AUC) of LDH was higher than SOFA score (AUC=0.637 v.s. 0.573, p=0.251).

CONCLUSION

This study identified serum LDH as an independent predictor of mortality in critically ill IE patients.