Outcomes of Patients Hospitalized With Community-Acquired, Health Care–Associated, and Hospital-Acquired Pneumonia

BACKGROUND: Traditionally, pneumonia has been classified as either community- or hospital-acquired. Although only limited data are available, health care-associated pneumonia has been recently proposed as a new category of respiratory infection. "Health care-associated pneumonia" refers to pneumonia in patients who have recently been hospitalized, had hemodialysis, or received intravenous chemotherapy or reside in a nursing home or long-term care facility. OBJECTIVE: To ascertain the epidemiology and outcome of community-acquired, health care-associated, and hospital-acquired pneumonia in adults hospitalized in internal medicine wards. DESIGN: Multicenter, prospective observational study. SETTING: 55 hospitals in Italy comprising 1941 beds. PATIENTS: 362 patients hospitalized with pneumonia during two 1-week surveillance periods. MEASUREMENTS: Cases of radiologically and clinically assessed pneumonia were classified as community-acquired, health care-associated, or hospital-acquired and rates were compared. RESULTS: Of the 362 patients, 61.6% had community-acquired pneumonia, 24.9% had health care-associated pneumonia, and 13.5% had hospital-acquired pneumonia. Patients with health care-associated pneumonia had higher mean Sequential Organ Failure Assessment scores than did those with community-acquired pneumonia (3.0 vs. 2.0), were more frequently malnourished (11.1% vs. 4.5%, and had more frequent bilateral (34.4% vs. 19.7%) and multilobar (27.8% vs. 21.5%) involvement on a chest radiograph. Patients with health care-associated pneumonia also had higher fatality rates (17.8% CI, 10.6% to 24.9% vs. 6.7% CI, 2.9% to 10.5%) and longer mean hospital stay (18.7 days CI, 15.9 to 21.5 days vs. 14.7 days CI, 13.4 to 15.9 days). Logistic regression analysis revealed that depression of consciousness (odds ratio OR, 3.2 CI, 1.06 to 9.8), leukopenia (OR, 6.2 CI, 1.01 to 37.6), and receipt of empirical antibiotic therapy not recommended by international guidelines (OR, 6.4 CI, 2.3 to 17.6) were independently associated with increased intrahospital mortality. LIMITATIONS: The number of patients with health care-associated pneumonia was relatively small. Microbiological investigations were not always homogeneous. The study included only patients with pneumonia that required hospitalization; results may not apply to patients treated as outpatients. CONCLUSION: Health care-associated pneumonia should be considered a distinct subset of pneumonia associated with more severe disease, longer hospital stay, and higher mortality rates. Physicians should differentiate between patients with health care-associated pneumonia and those with community-acquired pneumonia and provide more appropriate initial antibiotic therapy.