Prognostic role of elevated lactate in acute pulmonary embolism: A systematic review and meta-analysis

Previous studies have shown elevated lactate was a good predictor for the prognosis of pulmonary embolism (PE). However, due to low number of patients and different expression of blood lactate in separate study, these results are inconsistent. Therefore, the aim of this meta-analysis is to evaluate the relationship between increased lactate levels and adverse outcome in acute PE.

The literatures search was conducted in PubMed, Web of Science, and EMBASE until May 29, 2021.

Finally, 6 studies with 1706 patients were included in our meta-analysis. High lactate levels were markedly associated with overall mortality both in unselected PE patients (OR 5.13, 95% CI: 3.36-7.86, p < .00,001) and normotensive PE patients (OR 4.54, 95% CI: 2.64-7.80, p < .00,001), and PE-related short-term mortality in patients with elevated lactate was significantly higher than that in patients with normal levels (OR 9.05, 95% CI :4.08-20.10, p < .00,001). The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of lactate for predicting overall mortality in patients with acute PE were 0.67 (95% CI: 0.43-0.85), 0.73 (95% CI: 0.60-0.83), 2.5 (95% CI: 2.0-3.1), and 0.45 (95% CI: 0.26-0.78), respectively. The area under SROC curve (AUC) was 0.76 (95% CI: 0.73-0.80).

The result of our meta-analysis indicate that elevated blood lactate is a good predictor for overall mortality and short-term mortality in patients with acute PE, and can be routinely measured in risk stratification, but its prognostic role in patients with different risk classes still need to be verified.