Elsevier

The Lancet

Volume 394, Issue 10206, 12–18 October 2019, Pages 1365-1375
The Lancet

Series
Frailty: implications for clinical practice and public health

https://doi.org/10.1016/S0140-6736(19)31786-6Get rights and content

Summary

Frailty is an emerging global health burden, with major implications for clinical practice and public health. The prevalence of frailty is expected to rise alongside rapid growth in the ageing population. The course of frailty is characterised by a decline in functioning across multiple physiological systems, accompanied by an increased vulnerability to stressors. Having frailty places a person at increased risk of adverse outcomes, including falls, hospitalisation, and mortality. Studies have shown a clear pattern of increased health-care costs and use associated with frailty. All older adults are at risk of developing frailty, although risk levels are substantially higher among those with comorbidities, low socioeconomic position, poor diet, and sedentary lifestyles. Lifestyle and clinical risk factors are potentially modifiable by specific interventions and preventive actions. The concept of frailty is increasingly being used in primary, acute, and specialist care. However, despite efforts over the past three decades, agreement on a standard instrument to identify frailty has not yet been achieved. In this Series paper, we provide an overview of the global impact and burden of frailty, the usefulness of the frailty concept in clinical practice, potential targets for frailty prevention, and directions that need to be explored in the future.

Introduction

The condition of frailty is gaining international attention as the population of older adults rises globally. Frailty is characterised by a decline in functioning across multiple physiological systems, accompanied by an increased vulnerability to stressors.1, 2 It is associated with increased mortality, hospitalisation, falls, and admission to long-term care.1, 2 There is also much individual burden for a person living with frailty, including impaired quality of life and loneliness.3, 4

The concept of frailty is constantly evolving in the literature, and there is a progressive debate about how to define the condition.5 This debate aside, three important factors have remained consistent over the past decades in the conceptualisation of frailty.6 First, frailty is multidimensional, with physical and psychosocial factors playing a part in its development. Second, although its prevalence does increase with age, frailty is an extreme consequence of the normal ageing process. Third, frailty is dynamic, which means that an individual can fluctuate between states of severity of frailty.6

Frailty is potentially preventable, up to a probable point of no return when it becomes a pre-death phase. Therefore, strategies to prevent and slow the progression of frailty are paramount.7 To identify which people would benefit from such strategies, an expansive body of research has been devoted to developing tools to objectively quantify frailty, with persisting disagreements about the conceptual framework to be measured. In 2001, Fried and colleagues described the clinical presentation of frailty in terms of a physical phenotype, the clinical presentation of a definable biological syndrome.1 According to this frailty phenotype, an older adult is diagnosable with frailty if they score positive for three or more symptoms or signs out of five criteria. Also in 2001, Rockwood and Mitnitski introduced their frailty index, which is based on an accumulation of age-related deficits.8, 9 In their model, frailty is a continuous score summing signs, symptoms, disabilities, and diseases. The characteristics of these two concepts, which currently dominate the field, are listed in panel 1. Although the concepts differ, there is some common ground, as shown by overlap in determinants and identification of frailty.2

Key messages

  • The condition of frailty is associated with adverse outcomes and increased health-care costs

  • Frailty occurs in adults at any age, but it is more prevalent in older adults

  • The global impact of frailty is expected to increase due to population ageing, particularly in low-income and middle-income countries

  • Risk factors for the onset of frailty span across a wide range of sociodemographic, clinical, lifestyle-related, and biological factors

  • Considering the degree of frailty of a person in clinical practice could result in more patient-centred care and avoidance of harm in primary, secondary, and tertiary prevention of disease

  • Although the concept of frailty is increasingly being used in primary, acute, and specialist care, the translation from research to clinical practice remains a challenge for the coming years; specificity and standardisation of frailty measures is essential for progress

  • Longitudinal research on trends and trajectories is a high priority for the frailty research agenda, as well as randomised controlled trials focused on prevention or treatment of frailty

  • Using a life-course approach might increase our understanding of how frailty and its risk factors develop in earlier life stages, and could contribute to the development of public health strategies for frailty prevention

There is also controversy over whether frailty should encompass functional limitations, or whether it should be viewed as a pre-disability state. In addition, increased attention has been given to frailty subtypes, such as social frailty, nutritional frailty, and cognitive frailty.11 However, evidence for these subtypes is still limited. Another construct that has recently been proposed is the concept of intrinsic capacity, which emphasises the physical and mental capacities of an individual, instead of an approach focused on losses as captured by traditional frailty measures.12 The concept is endorsed by WHO but has not been empirically validated.

This is the first of a two paper Series on frailty, based on the latest evidence. In this paper, we describe the implications of frailty for clinical practice and public health. We will focus on frailty in older adults, but frailty can occur in adults at any age—especially in those with chronic illnesses. We provide an overview of the global impact and burden of frailty, including that in low-income and middle-income countries (LMICs), the usefulness of the frailty concept in daily practice, potential targets for frailty prevention, the importance of taking a life-course perspective, and the directions that need to be explored in the future. The description of preclinical models will not be covered in the present paper. The management of frailty, including interventions, is presented in the second paper.

Section snippets

Frailty prevalence

Frailty is present in millions of older adults worldwide. However, the global prevalence of frailty is not yet known, partly because frailty research has predominantly been done in high-income countries. Another reason is the use of different operational definitions of frailty across studies. One systematic review pooled findings from 61 500 older community-dwelling participants enrolled in studies from high-income countries and found a weighted average estimate of 11% for frailty. However,

Identification of frailty: why is it important?

Given the increasingly high prevalence of frailty and its strong association with numerous adverse health outcomes, the impact of frailty on the wellbeing of ageing individuals and the functioning of the overstretched health-care system is readily apparent. By considering a patient's degree of frailty in their day-to-day practice, clinicians can deliver more patient-centred care, which in turn might lead to better outcomes and avoidance of harm in primary, secondary, and tertiary prevention of

Contributors to frailty

Risk factors for the onset of frailty or frailty progression span a wide range of aspects and conditions, covering sociodemographic, clinical, lifestyle-related, and biological domains (figure 3).88 Insight into risk factors could guide public health and preventive strategies, in particular when these risk factors are potentially modifiable by specific interventions. For example, physical inactivity is recognised as one of the major contributing factors to frailty onset and progression, and

Future perspectives

Over the past decades, the clinical and research consensus has been that there is a subset of older adults with high vulnerability to adverse outcomes, including mortality and disability. Two major processes have emerged as drivers of these adverse outcomes: frailty and single diseases or multimorbidity. Frail older adults have a distinct underlying pathophysiology of dysregulation of multiple dynamic physiological regulatory systems, with compromised homoeostasis and resilience. When a

Conclusion

Frailty is highly prevalent and is associated with adverse outcomes and increased health-care costs. The global impact of frailty is expected to increase due to population ageing. Therefore, addressing frailty is an urgent public health need. The response should be a collective effort of older adults, health-care professionals, researchers, and policy makers both in high-income countries and in LMICs, where the population is ageing more rapidly than in many high-income countries, and where

Search strategy and selection criteria

We searched PubMed for articles published in English up to July 4, 2019, with the search terms “frail elderly”, “frailty”, “sarcopenia”, “frailty index”, and “frailty phenotype”. Additionally, we sought publications from the reference lists of identified papers and from our cumulative literature archives. Where possible, we gave priority to systematic reviews and studies published in the past 5 years.

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