Prognostic value of serum lactate level for mortality in patients with acute kidney injury

Abstract Background Serum lactate is associated with mortality in diverse kinds of patients. This study aimed to investigate whether serum lactate level may independently predict mortality in acute kidney injury (AKI) patients. Methods A total of 4461 AKI patients were collected from the Medical Information Mart for Intensive Care (MIMIC III) database and followed up for 365 days. According to serum lactate tertiles, participants were divided into three groups (Q1–Q3) by: Q1 ≤ 1.60 mg/dl, Q2 = 1.61–2.70 mg/dl, and Q3 ≥ 2.71 mg/dl. We calculated the hazard ratio (HR) and 95% confidence intervals (Cls) for mortality across each tertile of lactate by using the Q1 as reference and constructed four models to adjust for the HR of mortality. Results Nonsurvivors had significantly higher lactate compared with patients in the survival group. Mortality rate gradually elevated with the increase in serum lactate level (Q1: 29.30%, Q2: 33.40%, Q3: 37.40%). When compared with Q1 after adjustment of all confounders, the HRs of Q3 still was 1.20 (95% Cl 1.05–1.37). Conclusions This study demonstrated that high serum lactate levels were an independent predictor of mortality in AKI patients.