Trends in the incidence and treatment of necrotizing soft tissue infections: an analysis of the National Hospital Discharge Survey.

Necrotizing soft tissue infections are a rare but potentially fatal condition of the soft tissues caused by virulent, toxin-producing bacteria. In the United States, there is an estimated annual incidence of 0.04 cases per 1000 annually, but previous estimates of the Centers for Disease Control and Prevention had the incidence at 500 to 1500 cases yearly. Early reports of mortality were variable with rates ranging from 46 to 76% but outcomes have been improving over time. The National Hospital Discharge Survey was analyzed to study current trends in the demographics, incidence, use, and mortality of patients diagnosed with necrotizing soft tissue infections. The authors analyzed the 1999, 2002, and 2007 National Hospital Discharge Survey by using a sampling weighting method. A total of 13,648 cases of necrotizing soft tissue infections were identified in 2007. This represents an increase from 12,153 cases in 2002 and 6612 cases in 1999. In the 9 years from 1999 to 2007 the gross incidence of necrotizing soft tissue infections more than doubled. Hospital stay was essentially unchanged within study years, at 16 days. Mean age increased from approximately 50 years in 1999 to 54 years in 2007. Further, mortality went from 10.45% in 1999 to 9.75% in the 2007 survey. The population-adjusted incidence rate increased 91% in the studied years. Rising use of immunosupression, exponential growth in the incidence of obesity, and type 2 diabetes could be a major contributing factor. The mortality rate is far below the rate in reports published from as early as 20 years ago, and at 9.75% compares with modern case series, but is a more accurate measure of mortality in this condition.