Serum lactate dehydrogenase level is associated with in-hospital mortality in critically Ill patients with acute kidney injury

OBJECTIVE: Sixty percent of critically ill patients suffer from acute kidney injury (AKI) and 12% of them require renal replacement therapy during their ICU stay. However, we lack effective biomarkers to predict the mortality of critically ill patients with AKI. Few studies have investigated the association between lactate dehydrogenase levels and mortality in patients with AKI. METHODS: We conducted a retrospective cohort study with large samples, using a large database, the Multi parameter Intelligent Monitoring in Intensive Care III project. Clinical and demographic data were collected from the database by structure query language. Multiple models were constructed by stepwise methods to examine the association between lactate dehydrogenase (LDH) and in-hospital mortality. The predictive performance of LDH was assessed by ROC analysis and p values were calculated for trends. RESULTS: In the final analysis, 8436 patients met the inclusion criteria, and 1519 patients died during their hospital stay. The mortality rate increased with increasing LDH levels. The association between LDH and in-hospital mortality was almost linear (p < 0.001). A multiple logistic regression model indicated that LDH level was an independent predictor of in-hospital mortality (OR = 1.56, 95% CI (1.39–1.73), p < 0.001) and this effect remained stable in the subgroup analysis. Moreover, the combined AUC of LDH and SAPSII was 0.83. CONCLUSIONS: The LDH level, which can be easily assessed, is significantly and independently associated with in-hospital mortality, and could increase the predictive ability of SAPSII for in-hospital mortality in our study.