Writing in the second issue for March of the American Thoracic Society's peer-reviewed American Journal of Respiratory and Critical Care Medicine, Derek C. Angus, M.D., M.P.H., of the Department of Anesthesiology and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, along with five associates, examined 623,718 hospital admissions records of community-acquired pneumonia (CAP) patients by linking four major databases.

The investigators looked at all patients 65 and older who were hospitalized in acute-care hospitals with a diagnosis of CAP. CAP was defined as either bacterial pneumonia listed on the admission and discharge diagnoses or bacterial pneumonia listed on the discharge diagnosis coupled with a pulmonary complaint upon admission.

Among the total cases, there were 334,569 women (53.6 percent) and 289,249 men (46.4 percent)

The researchers organized their cohort data by age, sex and location prior to hospitalization, microbiological etiology, and underlying illness.

Although more women were included in the study group, the incidence rate was higher in the men (19.4 cases per 1,000 men versus 15.1 cases per 1,000 women).

"This higher incidence persisted across all age groups such that men had an incidence similar to that of women five years older," said Dr. Angus.

Overall, 22.5 percent of the cases were classified as complex. The researchers defined a "complex course" of pneumonia as one involving either intensive care unit (ICU) admission or mechanical ventilation.

The investigators identified 140,226 complex cases, of whom 95,589 (68.2 percent) received ICU care alone, 41,355 (29.5 percent) received ICU care with mechanical ventilation, and 3,282 (2.3 percent) obtained mechanical ventilation outside of the ICU.

Men were more likely to be managed as a complex case, both from an overall standpoint (24.4 percent versus 20.8 percent for women) and across all age groups.

The hospital mortality for the entire group was 10.6 percent. It doubled from 7.8 percent for those aged 65-69 to 15.4 percent for those over 90 years.

Mortality rates were higher in men than in women both from an overall standpoint (11.6 percent versus 9.8 percent) and within all age groups.

The researchers said that the burden of CAP would grow substantially in the coming years, with 750,000 cases projected for 2010, and 1 million for 2020. The reason noted was the disproportionate growth in the elderly populations.

Within the study group, the biomedical scientists found that mechanical ventilation for 90-year-old patients was provided commonly. They also discovered that almost half of the patients over age 90 who received mechanical ventilation were discharged alive, supporting the belief that "such care for the critically ill elderly patient is often justified."

The average hospital stay for CAP cases was 7.6 days and costs per admission were $6,949. For 1997, overall hospital costs for this diagnosis was $4.4 billion, of which $2.1 billion was incurred by cases managed in the ICU.

[Contact: Derek C. Angus M.D. M.P.H.]

21-Mar-2002