The Impact of Hospital-Acquired Bloodstream Infections

Richard P. Wenzel, Michael B. Edmond, Medical College of Virginia, Virginia Commonwealth University, Richmond, Virginia, USA


Emerging Infectious Diseases. 2001;7(2) 

In This Article

Number of Deaths from Nosocomial Infections

Several assumptions may be examined simultaneously regarding the attack rate and both crude and attributable mortality rate estimates (Figure 2). By doing so, deaths directly attributable to nosocomial bloodstream infections can be calculated, with a range of very conservative to more liberal estimates based on available data. For example, with a hospital infection rate of 5%, of which 10% are bloodstream infections, and an attributable mortality rate of 15%, 26,250 deaths can be directly linked to nosocomial bloodstream infections. However, if a 20% attributable mortality rate is assumed, the number of deaths is from 17,500 (with a 2.5% nosocomial infection rate) to 70,000 (with a 10% total nosocomial infection rate).

Figure 2. Estimated number of deaths caused by nosocomial infections in the United States each year. Attributable mortality rates are 10% to 30% on the X axis, and the three curves assume overall nosocomial infection rates of 21/2%, 5%, or 10%.

With various assumptions about total nosocomial infection rates and attributable mortality rate, the ranking of nosocomial bloodstream infections among leading causes of death can be estimated (Figure 3). This ranking reflects the total number of deaths compared with the reported numbers of leading causes of death in the United States[1]. From the above estimates, if nosocomial bloodstream infections alone were counted, they would represent the fourth to thirteenth cause of death in the United States.

Figure 3 Leading causes of death are ranked according to attributable mortality rate and compared with number of deaths from leading causes in the United States[1]

The impact of nosocomial bloodstream infections can also be examined in terms of years of life lost. SCOPE (M. Edmond, pers. comm.) indicates that the median age of patients dying of nosocomial bloodstream infections is 57 years. If these patients are 60 years of age, without bloodstream infection they would have lived to age 70. This assumption is reasonable since only attributable deaths are included in the calculations (Figure 4). As an example, if the attributable mortality rate is 20% and the total nosocomial infection rate is 5%, the total number of years of life lost in the United States would be 350,000 annually. If the attributable mortality rate were only 10%, the number of years of life lost annually would be 87,500 to 350,000, depending on the total infection rate.

Figure 4. Years of life lost annually in the United States from nosocomial infections. Attributable mortality rates are 10% to 30% on the X axis, and the three curves assume overall nosocomial infection rates of 21/2%, 5%, or 10%.


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