Rethinking the concepts of community-acquired and health-care-associated pneumonia.

The increasing numbers of patients who are elderly and severely disabled has led to the introduction of a new category of pneumonia management: health-care-associated pneumonia (HCAP). An analysis of the available evidence in support of this category, however, reveals heterogeneous and misleading definitions of HCAP, reliance on microbiological data of questionable validity, failure to recognise the contribution of aspiration pneumonia, failure to control microbial patterns for functional status, and failure to recognise frequently applied restrictions of treatment escalation as bias in assessing outcomes. As a result, the concept of HCAP contributes to confusion more than it provides a guide to pneumonia management, and it potentially leads to overtreatment. We suggest a reassignment of the criteria for HCAP to reconstruct the triad of community-acquired pneumonia (with a recognised core group of elderly and disabled patients and a subgroup of younger patients), hospital-acquired pneumonia, and pneumonia in immunosuppressed patients.