Validation and simplification of Fournier's gangrene severity index

Abstract

Objectives: To validate the predictive value of Fournier's Gangrene Severity Index in patients with Fournier gangrene and to facilitate patient mortality risk-stratification by simplifying the Fournier's Gangrene Severity Index.

Methods: From January 1989 to December 2011, 85 male patients with clinically-documented Fournier's gangrene undergoing intensive treatment and with complete medical records were recruited. The demographic information and nine parameters of Fournier's Gangrene Severity Index were compared between survivors and non-survivors. The parameters that showed a significant difference between the two groups were selected to generate a simplified scoring index.

Results: Of the 85 patients recruited, 16 patients died of the disease with mortality rate of 18.8%. The Fournier's Gangrene Severity Index score at initial diagnosis was significantly higher in non-survivors than in survivors. Of the nine parameters of Fournier's Gangrene Severity Index, the scores of serum creatinine level, hematocrit level and serum potassium level were significantly different between the two groups. However, the mean body temperatures, heart rate, respiration rate, white blood cell count, serum sodium and bicarbonate levels were non-significantly different. Of the 12 patients with chronic kidney disease or end-stage renal disease, 10 died of severe sepsis. A simplified scoring index including parameters of creatinine, hematocrit and potassium was generated, which provided sensitivity and specificity of 87% and 77% in predicting patient mortality, respectively. The predictive values of this simplified Fournier's Gangrene Severity Index were shown to be non-inferior to Fournier's Gangrene Severity Index in our patients.

Conclusions: The simplified Fournier's Gangrene Severity Index is easy to use at initial diagnosis, and offers a way to compare outcomes in different clinical populations.

Keywords: Fournier's gangrene; index; mortality; renal insufficiency; risk.