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

Abstract

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.