Prognostic value and clinical net benefit of global longitudinal strain in sepsis: a prospective study with internal bootstrap validation.

OBJECTIVE: Conventional left ventricular ejection fraction (LVEF) often fails to detect early sepsis-induced myocardial dysfunction (SIMD). This study aimed to evaluate the prognostic utility of speckle-tracking echocardiography (STE)-derived global longitudinal strain (GLS) and to develop an internally validated clinical nomogram with demonstrated net benefit for predicting 28-day mortality in sepsis patients. METHODS: This prospective observational study enrolled 46 patients presenting with sepsis or septic shock at the Emergency Department of The First Affiliated Hospital of Sun Yat-sen University (February-June 2023). STE-derived average GLS (GLS_AVG), conventional echocardiography, and cardiac biomarkers were evaluated within 24 h of diagnosis. Prognostic performance was assessed using restricted multivariable logistic regression, Receiver Operating Characteristic (ROC) curves, and DeLong's test. A predictive nomogram was constructed, validated via 1,000 bootstrap resamples, and evaluated for clinical utility using Decision Curve Analysis (DCA). RESULTS: The 28-day mortality rate was 23.9% (11/46). Compared to survivors, non-survivors exhibited significantly impaired GLS_AVG (-10.09 ± 4.18% vs. -14.69 ± 3.13%, P < 0.001) and higher SOFA scores (11.55 ± 3.11 vs. 7.63 ± 3.15, P = 0.001). GLS_AVG strongly correlated with SOFA (r = 0.663) and NT-proBNP peak (r = 0.424). ROC analysis demonstrated that GLS_AVG (AUC: 0.796) outperformed conventional LVEF (AUC: 0.706) in predicting mortality. The optimal GLS_AVG cutoff was > -11.0% (sensitivity 72.7%, specificity 82.9%). In restricted multivariable analysis, GLS_AVG showed a borderline independent association with 28-day mortality in the restricted multivariable model (OR: 1.266; 95% CI: 0.995-1.676; P = 0.067). The formulated GLS-SOFA nomogram showed excellent calibration upon 1,000-bootstrap internal validation. Crucially, DCA confirmed that integrating GLS yielded a substantially higher clinical net benefit across a wide range of threshold probabilities compared to relying on LVEF alone. CONCLUSION: STE-derived GLS is a highly sensitive, relatively load-independent marker of early myocardial dysfunction in sepsis, significantly outperforming LVEF in predicting 28-day mortality. The validated GLS-SOFA nomogram and decision curve models provide a practical, high-yield tool to enhance risk stratification and guide early personalized hemodynamic resuscitation in emergency settings.