Background and aim: Serum lactate levels are routinely measured in critically ill patients with cirrhosis, and hyperlactatemia is a common finding, but its prognostic value remains controversial. Our aim was to examine whether serum lactate level could be used as a predictor of outcome in critically ill patients with cirrhosis (CICP) with acute kidney injury (AKI).
Patients and methods: In this study, we included 480 consecutive patients with cirrhosis admitted to ICU, complicated with AKI, and were followed up for 365 days. Patients were divided into four groups (Q1-Q4) by serum lactate quartiles: Q1≤1.8 mg/dl, Q2=1.9-2.4 mg/dl, Q3=2.5-4.0 mg/dl, and Q4≥4.1 mg/dl. The hazard ratio (HR) and 95% confidence intervals (CIs) for hospital mortality were calculated across each quartile of serum lactate, using the Q1 as reference, and four models were built to adjust for the HR of mortality.
Results: Compared with patients in the survival group, nonsurvivors had higher serum lactate levels. Mortality rate increased progressively as the serum lactate level increased (Q1: 56.06%, Q2: 62.16%, Q3: 72.73% and Q4: 75.86%), and this relationship remained statistically significant after rigorous control of confounding factors in Q2, Q3, and Q4 with HRs of 1.03 (95% CI: 0.73-1.46), 1.40 (95% CI: 1.01-1.95), and 1.84 (95% CI: 1.28-2.64), respectively.
Conclusion: Our study brings a new perspective to the role of lactate monitoring in CICP with AKI. Elevated serum lactate levels are associated with a higher mortality rate in CICP with AKI. Elevated serum lactate levels should be part of rapid diagnosis and initiation of therapy to improve clinical outcome.