The following is a summary of “Can lactate levels and lactate kinetics predict mortality in patients with COVID-19 with using qCSI scoring system?,” published in the April 2023 issue of Emergency Medicine by Yadigaroğlu, et al.
For a study, researchers sought to investigate the predictive value of blood lactate levels and lactate kinetics (lactate clearance and Δ lactate) for mortality in COVID-19 patients admitted to the emergency department.
It was a retrospective study conducted on patients admitted to the emergency department between March 1st, 2020, and January 1st, 2022. The study analyzed lactate levels at admission (0 h lactate) and the highest lactate levels within the first 24 hours (2nd highest lactate). In addition, lactate kinetics were calculated, and clinical severity was determined using the quick COVID Severity Index (qCSI).
The study included 300 patients, and the 2nd highest lactate levels were significantly higher in the mortality group than in the group without mortality (P < 0.001). Lactate clearance and Δ lactate levels were also significantly lower in the mortality group (P < 0.001). The lactate kinetics were significantly lower in the mortality group in patients with low clinical severity (P = 0.02 and P = 0.039, respectively). In patients with high clinical severity, 2nd highest lactate levels were higher in the mortality group (P = 0.010), and lactate kinetics were significantly lower (P < 0.001). The AUC for 2nd highest lactate levels in predicting mortality was 0.642 (95% CI: 0.548–0.728) with an optimal cut-off value >2.4 mmol/L (60.6% sensitivity, 67.4% specificity). The AUC for lactate clearance was 0.748 (95% CI: 0.659–0.824), and the optimal cut-off value was ≤ −177.78% (49.3% sensitivity, 100% specificity). The AUC for Δ lactate was 0.707 (95% CI: 0.616–0.787), and the optimal cut-off value was ≤ −2 mmol/L (45.1% sensitivity, 93.5% specificity).
The study showed that 2nd highest blood lactate levels and lactate kinetics could be used as prognostic indicators of COVID-19. High 2nd highest lactate levels and low lactate kinetics in patients with high clinical severity can help guide physicians in determining the outcome of the disease.