Initial Lactate Level Affects the Relationship between Early Lactate Measurement and mortality in Septic Patients: a Cohort Study Based on the eICU-CRD database

Abstract Background. Previous studies have reported a negative association between early lactate measurement and mortality among septic patients with lactate levels > 2 mmol/L. However, this present association among septic patients with lactate less than 2mmol/L is unknown. Methods. This was a retrospective cohort study conducted in the United States with 208 distinct ICUs. The original data were extracted from a public database (eICU Collaborative Research Database). Our study only focused on septic patients. A multivariable logistic regression model was used to explore the association between the time of lactate measurement and 28-day mortality. Results. This study included 6334 participants (median [IQR] age, 67 [56–77] years; 3121 (49.3%) female) with the rate of 28-day mortality being 10.6% (671) after ICU admission. After full adjustment, logistic regression results found that the time to finish lactate measurement was associated with a higher risk of 28-day mortality among septic patients with lactate > 2 mmol/L (OR = 1.028 (95% CI, 1.004–1.053; P = 0.024). Similar results were observed among patients with lactate of 1–2 mmol/L (OR = 1.036,95%CI: 1.010–1.064; P = 0.007). In addition, for patients with remeasurement lactate > 2 mmol/L, the time to finish remeasurement of lactate was significantly associated with 28-day morality in the fully adjusted model (OR = 1.044; 95% CI, 1.016–1.073; P = 0.002.) Conclusion. Regardless of initial lactate 1–2 mmol/L or > 2 mmol/L, early lactate measurement could help to reduce the risk of 28-day mortality for septic patients. Repeating the measurement after the initial measurement is appropriate for patients whose remeasurement lactate was > 2 mmol/L. These findings need confirmation in other studies.