Health-care-associated pneumonia among hospitalized patients in a Japanese community hospital

Background: Health-care-associated pneumonia (HCAP) is a relatively new concept. Epidemiologic studies are limited, and initial empirical antibiotic treatment is still under discussion. This study aimed to reveal the differences in mortality and pathogens between HCAP and community-acquired pneumonia (CAP) in each severity class, and to clarify the strategy for the treatment of HCAP. Methods: We conducted a retrospective observational study of patients with HCAP and CAP who were hospitalized between November 2005 and January 2007, and compared baseline characteristics, severity, pathogen distribution, antibiotic regimens, and outcomes. In each severity class (mild, moderate, and severe) assessed using the A-DROP scoring system (ie, age, dehydration, respiratory failure, orientation disturbance, and low BP), we investigated the in-hospital mortality and occurrence of potentially drug-resistant (PDR) pathogens. Results: A total of 371 patients (141 HCAP patients, 230 CAP patients) were evaluated. The proportion of patients in the severe class was higher in the HCAP patients than in CAP patients. In the moderate class, the in-hospital mortality proportion of HCAP patients was significantly higher than that of CAP patients (11.1% vs 1.9%, respectively; p = 0.008). In moderate-class patients in whom pathogens were identified, PDR pathogens were isolated more frequently from HCAP patients than from CAP patients (22.2% vs 1.9%, respectively; p = 0.002). The occurrence of PDR pathogens was associated with initial treatment failure and inappropriate initial antibiotic treatment. Conclusions: The present study provides additional evidence that HCAP should be distinguished from CAP, and suggests that the therapeutic strategy for HCAP in the moderate class holds the key to improving mortality. Physicians may need to consider PDR pathogens in selecting the initial antibiotic treatment of HCAP.