A new paradigm for clinical investigation of infectious syndromes in older adults: assessing functional status as a risk factor and outcome measure.

Adults aged 65 and over comprise the fastest growing segment of the U.S. population, and older adults experience greater morbidity and mortality due to infection than young adults. While this factor is well established, most clinical investigation of infectious diseases in the aged focuses on microbiology, and crude endpoints of clinical success such as cure rates or mortality, but often fails to assess functional status, a critical variable in geriatric care. Functional status can be evaluated as a risk factor for infectious disease or an outcome of interest following specific interventions utilizing well-validated instruments. This paper outlines the currently available data suggesting a link between infection, immunity and impaired functional status in the elderly, summarizes commonly employed instruments used to determine specific aspects of functional status, and provides recommendations for a new paradigm in which clinical trials of older adults include functional assessment.