How important is age in defining the prognosis of patients with community-acquired pneumonia?

Abstract

Purpose of review: Given that the population is increasing in age, a better understanding of the relationship between chronological age and health-related outcomes (especially mortality) is needed, for both chronic diseases (e.g. diabetes) and acute illnesses (e.g. pneumonia). Our purpose was to review the impact of age on the prognosis of patients with community-acquired pneumonia (CAP).

Recent findings: Many studies in patients with CAP have suggested that chronological age is not necessarily independently associated with mortality. Poorer outcomes in the elderly with CAP have been related to severity of disease, comorbid disease burden, functional status, and frailty, but not to age alone. However, many of these studies suffer from 'over-adjustment' due to the use of unmodified severity scores such as the Pneumonia Severity Index or Acute Physiology and Chronic Health Evaluation II (that already include age) in multivariable analyses. Studies accounting for this over-adjustment suggest that age is, in fact, independently associated with mortality in hospitalized patients with CAP. Other outcomes including hospitalization and readmission rates, hospital length of stay, and cost of care are similarly associated with increasing age. Residual confounding is still a problem in many of the observational studies reviewed.

Summary: Contrary to conventional wisdom, chronological age is independently associated with adverse outcomes in patients with CAP. Until better methods (or more clinically-rich datasets) for observational studies are developed that can avoid over-adjustment and better deal with residual confounding, physicians should take into account both a patient's overall health status and his or her chronological age.