Prognostic value of the shock index in Fournier's gangrene: a retrospective cohort study comparing established mortality scoring systems.

backgroundFournier's gangrene is a rapidly progressive, life-threatening necrotizing infection of the perineal and genital re-gions, associated with persistently high mortality despite advances in surgical and intensive care. Early and reliable prognostic assess-ment is essential for improving patient outcomes. This study aimed to evaluate the prognostic performance of the Shock Index (SI) in predicting mortality in patients with Fournier's gangrene and to compare its discriminatory ability with established scoring systems.

methodsThis retrospective cohort study included adult patients diagnosed with Fournier's gangrene who presented to the emergency department of a tertiary university hospital and underwent surgical debridement between January 2015 and December 2024. Demographic, clinical, and laboratory data were extracted from institutional and national electronic health records. Survivors and non-survivors were compared using appropriate statistical tests. Variables associated with mortality were assessed using logistic regression analysis. Receiver operating characteristic (ROC) analysis was performed to evaluate the predictive performance of SI and conventional scoring systems, and the optimal SI cut-off for mortality prediction was determined using Youden's index.

resultsA total of 158 patients (mean age 62.3±13.4 years; 86.1% male) were included, with an overall mortality rate of 17.1%. Non-survivors were significantly older (p<0.001), and comorbidities including coronary artery disease, chronic heart failure, and chronic renal failure were significantly associated with mortality. At admission, non-survivors had higher heart and respiratory rates and lower systolic blood pressure. ROC analysis demonstrated that the Shock Index had the highest discriminatory performance for mortality prediction (area under the curve=0.952; 95% confidence interval 0.918-0.986; p<0.001), outperforming the Fournier Gan-grene Severity Index, Uludağ Fournier Gangrene Severity Index, Laboratory Risk Indicator for Necrotizing Fasciitis, and quick Sequen-tial Organ Failure Assessment. An optimal SI threshold of 0.866 yielded 92.6% sensitivity and 83.2% specificity.

conclusionThe Shock Index demonstrated superior prognostic accuracy compared with conventional scoring systems in patients with Fournier's gangrene. Given its simplicity and reliance on two readily available hemodynamic parameters, SI represents a practical tool for early risk stratification. Prospective, multicenter studies are needed to further validate its clinical utility.