Serum lactate level upon admission to the neuro-intensive care unit and 90-day mortality: A retrospective study

Abstract

The serum lactate level is a useful predictor of mortality in critically ill patients. However, little is known about the association between the serum lactate level and mortality in patients admitted to neurointensive care units (NCUs). The present study aimed to investigate the association between the initial lactate level and 90-day mortality in NCU patients. This retrospective observational study was conducted by reviewing the medical records of adult (age >= 18 years) patients admitted to the NCU at a single tertiary care academic hospital during 2013-2017. The initial lactate level (mmol L-1) was defined as the serum lactate level measured within 6 h following NCU admission. The final analysis included 2737 patients, of whom 280 (10.2%) died within 90 days of NCU admission. In a receiver operating characteristic (ROC) analysis, the estimated area under the curve (AUC) for the initial lactate level in predicting overall 90-day mortality was 0.55 [95% confidence interval (CI): 0.52-0.59]. The corresponding values for neurologic and non-neurologic disease-related 90-day mortality were 0.76 (95% CI: 0.71-0.82) and 0.49 (95% CI: 0.45-0.53), respectively. In a multivariable Cox regression analysis, a 1-mmol L-1 increase in the initial lactate level was associated with 1.17- and 1.22-fold increases in overall and neurologic disease-related 90-day mortality, respectively, but not with non-neurological disease-related 90-day mortality (P = 0.422). Elevated lactate levels were related with an increase in overall 90-day mortality among NCU patients. This association was specifically attributed to neurologic disease-related 90-day mortality. (C) 2019 Elsevier Ltd. All rights reserved.