Necrotizing fasciitis of the extremities in high and low Charlson Comorbidity Index: A multi-center retrospective cohort study

Abstract

Background: Necrotizing fasciitis (NF) is a life-threatening and acute progressive soft tissue infection and needs early surgical intervention, that is, debridement or amputation. Surgical strategy or prognosis is influenced by the speed of progression and patients' general condition, which can be calculated by the Charlson Comorbidity Index (CCI). The purpose of this study was to investigate the association between the CCI scores and prognosis of patients with NF of the upper/lower extremities.

Methods: In the retrospective cohort study, we analyzed patients with NF of the upper/lower extremities who were determined to undergo surgery by orthopedic surgeons at four tertiary hospitals between August 2003 and April 2016. We divided the patients into two groups, Group L (low CCI scores of 0-2) and Group H (high CCI scores of ≥3). The primary event of this study was defined as death or amputation. Mortality cases were included when amputation was informed with documented certification but patients died while waiting for surgery. We compared the patients' background, laboratory data on admission, the laboratory risk indicator for necrotizing fasciitis (LRINEC) score, and primary outcome between the two groups.

Results: Of the 56 patients, 28 patients were classified into Group L and the other 28 patients into Group H. The data in this study showed that patients in Group H had lower white blood cell counts and hemoglobin and higher creatinine than Group L, but there was no difference in LRINEC scores between the two groups. Streptococcus pyogenes was the most common infectious agent in Group L (54%) but not in Group H (11%). Poorer outcome was observed in Group H compared with Group L (4 mortality and 16 amputation vs. no mortality and 9 amputation, P = 0.007).

Conclusions: Laboratory data and causative microorganisms were different between high CCI and low CCI patients with NF. High CCI scores were associated with limb amputation or death caused by NF of the upper/lower extremities; whereas, low CCI scores were more likely associated with S. pyogenes monoinfection.

Keywords: Charlson Comorbidity Index; LRINEC score; Necrotizing fasciitis; S.pyogenes; amputation.