Lactate measurements accurately predicts 1-week mortality in emergency department patients with acute kidney injury

BACKGROUND: Studies on prognostic indicators in patients with acute kidney injury are limited. This study investigated 1-week mortality, laboratory and clinical parameters according to the lactate levels in patients with acute kidney injury. METHODS: In this cross-sectional study, we compared the lactate levels on admission and follow-up in emergency department with vital findings, laboratory parameters, and 1-week mortality. RESULTS: Data of 3375 patients examined; 2681 patients excluded and 694 patients were included. Median lactate level on admission was 1.6 (1.1–2.5) mmol/L for patients who discharged from emergency department, 2.2 (1.3–3.4) mmol/L for patients admitted to the hospital wards, 3.7 (1.7–7.2) mmol/L for patients admitted to the intensive care unit and 4.4 (2.4–8.0) mmol/L for patients with mortality within 1-week of ED presentation. Mortality was 30.4% in patients with high lactate levels and 8.1% in patients with normal lactate levels on admission. (p < 0.001, odds ratio 5.0, 95% CI 3.2–7.7) Elevated lactate level was independent risk factor for 1-week-mortality. (p < 0.001, odds ratio 1.138, 95% CI 1.067–1.214) Patients with high lactate levels have low systolic blood pressure, diastolic blood pressure, oxygen saturation, pH, base deficit, and bicarbonate, and higher heart rate and respiratory rate. The mortality of patients with normal lactate levels on admission was 8.1%, while mortality rate increased to 19% if elevated lactate levels observed during emergency department follow-up. CONCLUSIONS: Elevated lactate level predicts 1-week mortality in patients presenting with acute kidney injury in emergency department. Elevated lactate level were associated with poorer vital signs and abnormal laboratory results.