The Canadian Initiative on Frailty and Aging

In all developed countries the absolute number and the proportion of the population aged over 65 is growing exponentially, as is that of the oldest old. Canada, which has one of the most rapidly aging populations, experienced a growth of 41% of those aged 80 and over between 1991 and 2001. A similar increase is also expected in the following ten years.

With the growth of the older population there has been increasing concern about its well-being, both from the perspective of the individual and that of society, which is faced with the challenges of meeting their health and social care needs. Functional decline is a major health problem, particularly in aging countries. The prevalence of disabilities increases dramatically with age from 30% in those aged 65 to 74, to 50% in the 75-84 age group and 80% for those over 85. The annual incidence of functional decline in community-dwelling people over 75 years of age is nearly 12%. While the great majority of older people consider themselves to be in good health and lead independent lives, a significant proportion, 10-20% depending on the definition, would be classified as frail by health care providers and/or researchers.

As such, the growth in the numbers of elders is paralleled by an increasing interest in the concept of frailty, reflecting the growing impact of frailty and the potential to improve the health of a significant segment of the population. In the past two decades, there has been a substantial growth in the body of literature on frailty. However, there is still no consensus on the definition and criteria used to describe frailty, and little knowledge on the quality of evidence related to the concept.

It is in this context that the Canadian Initiative on Frailty and Aging was initiated with the overall goals of furthering our understanding of the causes, implications and trajectory of frailty and improving the lives of older persons at risk of frailty by dissemination knowledge on its prevention, detection and treatment as well as the cost-effective organization of services.

The specific objectives of the Canadian Initiative on Frailty and Aging are:

• to summarize the present state of research on frailty in older persons in order to develop a working framework and identify research priorities which could be used to develop a program of enquiry;

• to make recommendations to primary health care providers and specialists on  detection and care of older persons who become frail;

• to propose policy recommendations to decision-makers and administrators of the health care system and to develop greater public awareness of frailty and the potential for its prevention and treatment.

The systematic literature review

As part of the first phase of the initiative, a systematic review of the literature is being carried out. The approach is intended to be broad and integrative from a variety of perspectives. The review includes all aspects of frailty, from its biological antecedents to its social, economic, psychological and quality of life consequences. It is intended to be relevant to researchers, medical and social care professionals and the wider community, as well as informing health and social care policy. The involvement of investigators and collaborators from Canada, Europe, Israel, USA, Japan, Singapore, Latin America ensures its relevance across a variety of cultures. The research is starting from a broad and flexible perspective, without a hypothesis as to a frailty model. It is intended that a consensus on frailty will emerge through the process of the critical review of the existing evidence and exchanges between the investigators.

Objectives of the systematic review

The objectives of the systematic literature review are to collate, critically review and synthesize the evidence and identify the gaps in the literature and in existing and emerging Canadian and international research. The results will be disseminated through the publication of a series of papers.

Methodology for the systematic review

Due to the vast and multidisciplinary nature of the literature on frailty, the systematic review was divided into 10 domains and research questions were developed for each, by experts in each field. Within each domain, the existing frailty literature was identified, and the quality of evidence assessed using standardised methods. The table  presents the domains and the domain-specific research questions.

Table: Domains and research questions addressed in the systematic literature reviews conducted by the Canadian Initiative on Frailty and Aging

A working framework for frailty

Although the literature review is not yet complete, a tentative working framework has emerged. A complex entity such as frailty is likely to have a complex etiology. The Canadian Initiative considers that the biological, psychological, social, and environmental factors that interact across the life course are the determinants of frailty. The life course approach to chronic disease provides an attractive framework for understanding frailty and its determinants. As applied to frailty, it is an integrative approach that considers biological, social, clinical, cognitive, psychological, and environmental factors interacting across a person’s lifespan that may either promote healthy aging or the emergence of frailty. Both early and late life factors are important to consider in identifying risk/protective factors for the development and progression of frailty. Rather than creating false dichotomies, biological and social risk factors are integrated.

Studies of risk factors for frailty or characteristics associated with frailty support the use of this approach. For example, data from the 1946 British birth cohort study showed that low birth weight was associated with decreased grip strength and increased risk of diabetes and cardiovascular disease some 50 years later. Studies examining risk factors in mid and late life have identified several biological, psychological, and social factors (cognitive impairment; depression; disease burden; increased/decreased BMI; lower extremity function limitation; decreased social contacts; low physical activity; no compared to moderate alcohol consumption; poor self-perceived health; smoking; vision impairment) that are predictive of later life functional decline. Risk factors shown to be associated with subsequent frailty include heavy drinking, physical inactivity, poor perceived health, having two or more chronic symptoms and having one or more chronic conditions. Among the demographic variables that have been assessed, increasing age and having less than 12 years of education are shown to be significantly associated frailty.

In developing a working framework, the Canadian Initiative on Frailty and Aging considers that frailty is a measurable syndrome that can be identified in older persons with a combination of some or all of a number of candidate components that need to be considered in the study of frailty. Certainly, work by Linda Fried and colleagues has identified the core of those components. These are weakness, poor endurance, reduced physical activity, slow gait, and unintentional weight loss. In addition, we hypothesise that cognitive decline and depressive symptoms may also be among the core components of frailty. The pathway from frailty to its adverse outcomes is affected by various biological, psychological, social, and societal modifiers which have been described by some researchers as the assets and deficits of an individual in their specific context.

Figure: Working framework for frailty

This framework points to the potential for health promotion, prevention and management.  Observational studies on aging suggest associations between several lifestyle factors and the onset of frailty. These findings provide opportunities for the development of interventions to promote healthy aging, reduce the incidence of frailty, delay its onset and/or reduce the number of years of dependency. Secondary prevention with early detection and treatment of certain chronic conditions such as hypertension, diabetes, heart disease, osteoporosis, etc. could play an important role as well.

Effective programs for the care of frail individuals can minimize the impact on the individual, their families, and society. Evidence suggests that comprehensive, integrated health and social service interventions for the frail elderly population may have an important impact on health, quality of life, satisfaction, caregiver burden, pattern of health care utilization and cost. Continuing functional decline is not inevitable in frail older people.  Exercise and rehabilitation have the potential to improve their functional state.  The introduction of assistive technologies for physically or cognitively impaired people could have an important impact on the quality of life of both caregivers and care-receivers.

Conclusion

Although there continues to be active debate on the exact nature of frailty, there is no disagreement about its impact on the older individual, their family and in particular those involved in care giving as well as society as a whole. It is clear that further study is necessary in order to advance the quality and strength of the evidence on frailty across the biological, clinical, population, and social domains. Certain key issues need to be addressed including the difference between frailty and aging, its determinants and pathophysiology, the identification of its core components, modifiers of its progression, and the relationship between the biological, cognitive, psychological, and social factors.

The multi-factorial aspects of frailty reflect the essence of care for older persons.  It moves away from an organ-by-organ to an integrative approach. Ultimately, work on frailty will be relevant to clinicians, older individuals, and society by identifying effective health promotion, prevention, treatment, rehabilitation, and care interventions.