Mortality, morbidity, and a billion-dollar bill
The fatality rates for hospital-associated pneumonia in general, and of ventilator-associated pneumonia (VAP) in particular, are high. For hospital-associated pneumonia, attributable mortality rates of 20% to 33% have been reported, according to the draft pneumonia prevention guideline by the Centers for Disease Control and Prevention (CDC).1 Here are some other findings gleaned from the draft document:
• In one study, VAP accounted for 60% of all deaths due to hospital-associated infections. In studies in which invasive techniques were used to diagnose VAP, the crude mortality rates ranged from 4% in patients with VAP — but without antecedent antimicrobial therapy — to 73% in patients with VAP caused by Pseudomonas or Acinetobacter species. Attributable mortality rates ranged from 5.8% to 13.5%.
• The wide ranges in crude and attributable mortality rates strongly suggest that a patient’s risk of dying from VAP is affected by multiple other factors, such as underlying disease, organ failure, receipt of antimicrobial agent, and the type of infecting organism.
• Analyses of pneumonia-associated morbidity have shown that hospital-associated pneumonia can prolong ICU stay by an average of 4.3 days and hospitalization by four to nine days. A conservative estimate of the direct cost of excess hospital stay due to pneumonia in 1993 was $1.2 billion a year for the nation.
• Pneumonia accounts for approximately 15% of all hospital-associated infections and 27% and 24% of all infections acquired in the medical intensive-care unit (ICU) and coronary care unit, respectively. It is the second most common hospital-associated infection after that of urinary tract.
• The primary risk factor for the development of hospital-associated bacterial pneumonia is mechanical ventilation (with its requisite endotracheal intubation). The CDC’s National Nosocomial Infection Surveillance System (NNIS) reported that in 1986-1990, the median rate of VAP per thousand ventilator-days in NNIS hospitals ranged from 4.7 in pediatric ICUs to 34.4 in burn ICUs. The median rate of nonventilator-associated pneumonia per 1,000 ICU days ranged from zero in pediatric and respiratory ICUs to 3.2 in trauma ICUs.
• Studies indicate that patients receiving continuous mechanical ventilation have six to 21 times the risk of developing hospital-associated pneumonia compared with patients who are not vented. Because of this tremendous risk, in the last two decades, most of the research on hospital-associated pneumonia has been focused on VAP.
1. Centers for Disease Control and Prevention. Healthcare Infection Control Practices Advisory Committee. Draft Guideline For Prevention Of Healthcare-Associated Pneumonia. Atlanta; 2002.