Description
Necrotizing fasciitis (NF) is a rare, but severe disease, which is one of the complications of invasive group A Streptococcal (GAS) infection. The Centers for Disease Control and Prevention estimates roughly 9000-11,500 cases of invasive GAS infections occur annually in the United Stated. About 6-7% of these patients have necrotizing fasciitis and approximately 25% of necrotizing fasciitis cases may be fatal. The purpose of this study is to identify and analyze potential risk factors associated with adverse outcomes in GAS necrotizing fasciitis patients in San Diego County, CA from mid 1994 to 2007. San Diego Health and Human Services Agency (HHSA), Epidemiology program conducted a passive surveillance of invasive GAS infection from June 1994 through December 2007. Over these 13.5 years, approximately 150 cases of GAS necrotizing fasciitis have been reported to the County of San Diego. Disease investigation has included confirmation of the diagnosis and collection of patient characteristics, including demographics, medical history, and outcome. A case of adverse outcome from NF was defined as death, renal impairment, adult respiratory distress syndrome, disseminated intravascular coagulation, multi-system organ involvement, or amputation. Cases of severe complications from necrotizing fasciitis were compared to patients with mild or no complications from NF. Risk factors, including demographics, site of infection, initial clinical presentation, and underlying illness, were analyzed using SPSS (v.15.0). There were total of 147 GAS necrotizing fasciitis cases reported from mid 1994 to 2007. Of those, 43 cases (29%) had adverse outcomes from the disease. NF patients of age 60 or older were 3.17 times (95%CI 1.19 - 8.41) more likely to have adverse outcomes than those who were younger than 60 years old (p<0.05). Streptococcal toxic shock syndrome and bacteremia were significantly associated with adverse outcomes in NF patients [OR=19.71 (95%CI 3.48 - 111.50) and OR=7.28 (95%CI 2.90 - 18.28), respectively; p<0.05]. Patients with injury or surgery to the area prior to onset of the disease were 2.63 times (95%CI 1.03 - 6.67) less likely to have adverse outcomes than those without preceding injury or surgery (p<0.05). Advanced age, bacteremia and streptococcal toxic shock syndrome are significantly associated with adverse outcomes in NF patients; whereas, preceding injury or surgery seems to be a protective factor from adverse outcomes of the disease.
