Impact of lactate dehydrogenase on prognosis of patients undergoing cardiac surgery

BACKGROUND: Lactate dehydrogenase (LDH) has been reported in multiple heart diseases. Herein, we explored the prognostic effects of preoperative LDH on adverse outcomes in cardiac surgery patients. METHODS: Retrospective data analysis was conducted from two large medical databases: Medical Information Mart for Intensive Care (MIMIC) III and MIMIC IV databases. The primary outcome was in-hospital mortality, whereas the secondary outcomes were 1-year mortality, continuous renal replacement therapy, prolonged ventilation, and prolonged length of intensive care unit and hospital stay. RESULTS: Patients with a primary endpoint had significantly higher levels of LDH (p < 0.001). Multivariate regression analysis presented that elevated LDH was independently correlated with increased risk of primary and secondary endpoints (all p < 0.001). Subgroup analyses showed that high LDH was consistently associated with primary endpoint. Moreover, LDH exhibited the highest area under the curve (0.768) for the prediction of primary endpoint compared to the other indicators, including neutrophil–lymphocyte ratio (NLR), lymphocyte-monocyte ratio (LMR), platelet–lymphocyte ratio (PLR), lactate, and simplified acute physiology score (SAPS) II. The above results were further confirmed in the MIMIC IV dataset. CONCLUSIONS: Elevated preoperative LDH may be a robust predictor of poor prognosis in cardiac surgery patients, and its predictive ability is superior to NLR, LMR, PLR, lactate, and SAPS II. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12872-022-02848-7.