Influence of age-adjusted shock index trajectories on 30-day mortality for critical patients with septic shock.

BACKGROUND

Septic shock poses a high mortality risk in critically ill patients, necessitating precise hemodynamic monitoring. While the age-adjusted shock index (ASI) reflects hemodynamic stability, the prognostic value of its dynamic trajectory remains unexplored. This study evaluates whether dynamic 24-h ASI trajectories predict 30-day mortality in septic shock patients.

METHODS

This retrospective cohort study extracted data from the MIMIC-IV (derivation cohort, = 2,559) and eICU-CRD (validation cohort, = 2,177) databases. The latent category trajectory model (LCTM) classified ASI changes within 24 h of intensive care unit (ICU) admission. The association between ASI trajectory categories and 30-day mortality was evaluated using Kaplan-Meier (KM) method and Cox proportional-hazard models, reported as hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULT

Three distinct ASI trajectories were explored: persistently low (Classes 1), initial high ASI sharply decreasing followed by instability (Classes 2), and steady ASI increase (Classes 3). KM curve revealed significantly higher 30-day mortality in Class 2 (32.1%) and Class 3 (38.7%) than Class 1 (12.3%) ( < 0.001). After fully adjusting for covariates, Class 2 (HR = 1.68, 95% CI: 1.25-2.25, = 0.001) and Class 3 (HR = 1.87, 95% CI: 1.26-2.77, = 0.002) showed elevated mortality risks in the derivation cohort. Validation cohort results were consistent (Class 2: HR = 1.92, 95% CI: 1.38-2.68, = 0.001) and (Class 3: HR = 1.66, 95% CI: 1.09-2.54, = 0.019). Triple-robust analyses and subgroup analyses confirmed the reliability of the results.

CONCLUSION

Dynamic 24-h ASI trajectories independently predict 30-day mortality in patients with septic shock, with unstable or rising patterns signaling high-risk subgroups. This underscores the clinical utility of real-time ASI monitoring for early risk stratification and tailored intervention.