Association between dynamic lactate trajectories and prognosis in patients with sepsis-associated acute respiratory distress syndrome (SA-ARDS): a cohort study

Static lactate levels inadequately reflect disease progression in sepsis-associated acute respiratory distress syndrome (SA-ARDS), which limits the accuracy of individualized prognostic assessment. This study aimed to identify the classification characteristics of 24-h dynamic lactate trajectories in SA-ARDS patients and evaluate their association with 28-day mortality. Using K-means clustering, we identified lactate trajectories in 931 SA-ARDS patients and validated in an independent MIMIC-IV cohort ( n = 621). Associations with mortality were assessed via multivariate regression, propensity score matching (PSM), and inverse probability treatment weighting (IPTW). Four trajectories emerged: plateau (Trajectory 1), decreasing (Trajectory 2), transient increase-then-decrease (Trajectory 3), and progressive hyperlactatemia (Trajectory 4). Mortality increased across trajectories (21.2% to 76.9%; P < 0.0001). Trajectories 3 (OR 2.53, 95% CI 1.10–5.90) and 4 (OR 6.73, 3.18–14.63) independently predicted mortality, confirmed in PSM and IPTW analyses. External validation and sensitivity analysis further supported the robustness of these findings replicated trajectory patterns and mortality associations. In SA-ARDS, 24-h lactate trajectories exhibit four distinct patterns, with Trajectories 3 and 4 independently predicting 28-day mortality. This approach supports risk stratification after the first 24-h observation period though its utility for immediate urgent clinical decision-making remains to be further investigated.