Geriatric syndromes: clinical, research, and policy implications of a core geriatric concept

Abstract

Geriatricians have embraced the term "geriatric syndrome," using it extensively to highlight the unique features of common health conditions in older people. Geriatric syndromes, such as delirium, falls, incontinence, and frailty, are highly prevalent, multifactorial, and associated with substantial morbidity and poor outcomes. Nevertheless, this central geriatric concept has remained poorly defined. This article reviews criteria for defining geriatric syndromes and proposes a balanced approach of developing preliminary criteria based on peer-reviewed evidence. Based on a review of the literature, four shared risk factors-older age, baseline cognitive impairment, baseline functional impairment, and impaired mobility-were identified across five common geriatric syndromes (pressure ulcers, incontinence, falls, functional decline, and delirium). Understanding basic mechanisms involved in geriatric syndromes will be critical to advancing research and developing targeted therapeutic options, although given the complexity of these multifactorial conditions, attempts to define relevant mechanisms will need to incorporate more-complex models, including a focus on synergistic interactions between different risk factors. Finally, major barriers have been identified in translating research advances, such as preventive strategies of proven effectiveness for delirium and falls, into clinical practice and policy initiatives. National strategic initiatives are required to overcome barriers and to achieve clinical, research, and policy advances that will improve quality of life for older persons.

Figure 1

Schematic conceptual representation of clinical conditions defined by the terms “disease”, “syndrome” and “geriatric syndrome”, illustrating differences in numbers and complexity of relevant factors, including etiological risk factors, pathophysiologic mechanisms and presenting symptoms. Adapted with permission from Olde Rikkert et al. (5).

Figure 2

A unifying conceptual model demonstrates that shared risk factors may lead to geriatric syndromes, which may in turn lead to frailty, with feedback mechanisms enhancing the presence of shared risk factors and geriatric syndromes. Such self-sustaining pathways may result in poor outcomes involving disability-dependence, nursing home placement, and ultimately death, thus holding important implications for elucidating pathophysiologic mechanisms and designing effective intervention strategies.

Figure 3

Mechanistic research addressing the pathophysiology of complex multifactorial geriatric syndromes will require the development of new conceptual models. The traditional linear model (A) has proven highly effective for the discovery of pathophysiologically relevant mechanisms in conditions such as inborn errors of metabolism, yet it does not adequately capture the multifactorial nature of geriatric syndromes. The concentric model (B) was developed by cancer researchers as a means of designing more effective cancer treatments by targeting multiple distinct oncogenic pathways(97). This approach may also not be suitable for geriatric syndromes since interventions targeting only one risk factor would address only a small portion of the overall risk for such conditions, while multi-component pharmaceutical interventions risk being unfocussed and could lead to adverse effects typically associated with geriatric polypharmacy. We propose an interactive concentric model (C) as a means of reconciling the need for mechanistic research with the conditions’multifactorial complexity, by focusing on pathways associated with risk factor synergisms, thus offering a locus for the design of targeted interventions. Modified from Decker and Sausville(97)