Predictors of mortality and limb loss in necrotizing soft tissue infections

Abstract

Hypothesis: Necrotizing soft tissue infections are associated with a high mortality rate. We hypothesize that specific predictors of limb loss and mortality in patients with necrotizing soft tissue infection can be identified on hospital admission.

Design: A retrospective cohort study.

Setting: A tertiary care center.

Patients: Patients with a diagnosis of necrotizing soft tissue infection during a 5-year period (1996-2001) were included. Patients were identified with International Classification of Diseases, Ninth Revision hospital discharge diagnosis codes, and diagnosis was confirmed by medical record review.

Interventions: Standard current treatment including early and scheduled repeated debridement, broad-spectrum antibiotics, and physiologic and nutritional support was given to all patients.

Main outcome measures: Limb loss and mortality.

Results: One hundred sixty-six patients were identified and included in the study. The overall mortality rate was 16.9%, and limb loss occurred in 26% of patients with extremity involvement. Independent predictors of mortality included white blood cell count greater than 30 000 x 10(3)/microL, creatinine level greater than 2 mg/dL (176.8 micromol/L), and heart disease at hospital admission. Independent predictors of limb loss included heart disease and shock (systolic blood pressure <90 mm Hg) at hospital admission. Clostridial infection was an independent predictor for both limb loss (odds ratio, 3.9 [95% confidence interval, 1.1-12.8]) and mortality (odds ratio, 4.1 [95% confidence interval, 1.3-12.3]) and was highly associated with intravenous drug use and a high rate of leukocytosis on hospital admission. The latter was found to be a good variable in estimating the probability of death.

Conclusions: Clostridial infection is consistently associated with poor outcome. This together with the independent predictors mentioned earlier should aid in identifying patients on hospital admission who may benefit from more aggressive and novel therapeutic approaches.