Fournier gangrene is a fulminant necrotizing fasciitis of the perineum and external genitalia that progresses rapidly and carries substantial morbidity and mortality. The disease often requires urgent surgical debridement, broad-spectrum antimicrobial therapy, hemodynamic support, and intensive care [[1], [2], [3]]. Because tissue loss, sepsis, and multi-organ dysfunction can evolve within hours, early risk stratification at presentation is critical to guide the timing and intensity of interventions and to inform discussions with patients and families [[4], [5], [6]].

Risk of death in Fournier gangrene is influenced by host factors such as advanced age, diabetes mellitus, immunosuppression, malnutrition, and underlying malignancy, as well as by the extent of infection and the presence of organ dysfunction on admission. Reported mortality rates vary widely across series, reflecting differences in case mix, referral patterns, and local practices, but remain clinically meaningful and underscore the need for reliable prognostic tools that can be applied at the time of initial assessment [7,8].

Clinical scoring systems that combine demographic, physiologic, and simple laboratory measures offer a structured approach to prognostication. Such scores can help triage patients for urgent surgery, prioritize critical care resources, and serve as standardized measures for benchmarking and research. However, many prognostic indices are developed in single centers and require independent validation before they can be recommended for general clinical use [6,[9], [10], [11], [12]]. Validation studies are necessary to determine whether a score retains its discriminative ability across different populations and care settings and to identify potential limitations or areas for refinement.

The Fournier Gangrene Mortality Index, recently proposed by Yönder and colleagues, integrates readily available admission variables including age, serum creatinine, serum albumin, lymphocyte percentage, and the neutrophil-to-lymphocyte ratio into a composite score intended to predict mortality [13]. Initial derivation work reported promising discrimination, yet external validation is limited, and it remains uncertain how the FGMI performs in cohorts with different baseline risk and management pathways.

Accordingly, the primary aim of the present study was to externally validate the FGMI in a consecutive cohort of patients with Fournier gangrene treated at our tertiary care center. By assessing the score's discrimination, calibration, and diagnostic accuracy for in-hospital mortality we seek to determine its clinical utility in our setting and to provide evidence to inform broader adoption or further refinement.

Additionally, the purpose of this prognostic model is not to identify patients in whom surgical intervention may be delayed, but rather to recognize at an early stage those who remain at high risk despite appropriate and timely surgical and medical management, thereby facilitating decisions regarding intensive monitoring, ICU admission, and resource allocation.