Untangling the Concepts of Disability, Frailty, and Comorbidity: Implications for Improved Targeting and Care

Abstract

Three terms are commonly used interchangeably to identify vulnerable older adults: comorbidity, or multiple chronic conditions, frailty, and disability. However, in geriatric medicine, there is a growing consensus that these are distinct clinical entities that are causally related. Each, individually, occurs frequently and has high import clinically. This article provides a narrative review of current understanding of the definitions and distinguishing characteristics of each of these conditions, including their clinical relevance and distinct prevention and therapeutic issues, and how they are related. Review of the current state of published knowledge is supplemented by targeted analyses in selected areas where no current published data exists. Overall, the goal of this article is to provide a basis for distinguishing between these three important clinical conditions in older adults and showing how use of separate, distinct definitions of each can improve our understanding of the problems affecting older patients and lead to development of improved strategies for diagnosis, care, research, and medical education in this area.

Clinical Phenotypes in Heart Failure With Preserved Ejection Fraction

“…As a concept, frailty differs from comorbidity, which is the cooccurrence of multiple conditions 243, 244. Frailty can be primary as a consequence of aging or secondary attributable to the presence of comorbidity 245.…”

Association of Frailty and Long‐Term Survival in Patients Undergoing Coronary Artery Bypass Grafting

“…It is increasing in prevalence and presents a formidable challenge for clinicians who work to optimize these patients 5. Frailty is a common syndrome described as a diminished resiliency in response to stress as a result of decreased physiological reserve, increased burden of comorbidities, and altered multisystem homeostasis 6. Frailty increases susceptibility to adverse health outcomes and contributes to the difference between chronological and physiological age 7.…”

Complex health problems in the oldest old in Sweden 1992–2002

“…Single variables may not give a comprehensive picture of health status and the necessary integration of medical and social services. Attention to complex health profiles is increasing (Bortz 2002;Fried et al 2004;Rockwood et al 2000) but most studies have been cross-sectional at one point of time.…”

“…Modified by social, economic and behavioral factors, as well as access to medical care, both multimorbidity and frailty are underlying causes for disability and other adverse health outcomes, including mortality and need for long-term care. Disability may, in turn, exacerbate frailty and multimorbidity (Fried et al 2004).…”

“…Estimations of prevalence rates vary from 6 to 40% and depend highly on how the term was operationalized, age groups studied, as well as whether institutionalized persons and cognitively impaired persons are included. Most studies find higher prevalence rates for women and older age groups (Brayne et al 2001;Fried et al 2004; The Canadian Study of Health and Aging Working Group 2001).…”