Dr. Roman Romero-Ortuno (@rrorthy7) is a newly appointed Consultant Geriatrician at Addenbrooke’s Hospital, Cambridge. In this blog, he outlines the scientific underpinnings of frailty and how this emerging science will lead to greater personalisation of treatments.
Frailty is vulnerability to decompensation after a stressor event and is a consequence of cumulative decline in many physiological systems during a lifetime.
Campbell & Buchner defined frailty as ‘a condition or syndrome which results from a multi-system reduction in reserve capacity to the extent that a number of physiological systems are close to, or past, the threshold of symptomatic clinical failure; and as a consequence the frail person is at increased risk of disability and death from minor external stresses’.
In clinical care provision, some interventions can be more ‘aggressive’ than others and hence more complication-prone. Frail (vulnerable) adults are more likely than ‘robust’ adults to suffer complications from a given medical intervention. While ‘fit’ people are resilient and ‘frail’ people are vulnerable, chronological age per se cannot tell where a person is along the ‘fitness-frailty’ spectrum, due to the great biological heterogeneity of the population of older people. Frailty more closely relates to the biological than to the chronological age of individuals.
The measurement of frailty as a surrogate for vulnerability in healthcare delivery is therefore of utmost importance in a current world characterised by an ageing population and continuing efforts to not only prevent and minimise iatrogenic events, but also concentrate the use of public resources in interventions for older people that are effective and evidence-based.
As an intuitive concept, frailty (i.e. vulnerability) is well recognised clinically. However, the objective measurement (i.e. operationalisation) of the concept is still a matter of debate and there is no agreed gold standard. Instead, there are several approaches to definition, two of the most popular being the frailty phenotype (i.e. frailty as a syndrome) and the frailty index (i.e. frailty as a state). Rather than being competitive or mutually exclusive, both approaches are complementary and suitable for different purposes or scenarios.
According to the phenotypic approach, frailty is defined as a clinical syndrome in which three or more of the following criteria are present: unintentional weight loss, self-reported exhaustion, weakness, slow walking speed, and low physical activity. According to this approach, co-morbidity is a risk factor for frailty, and frailty is a precursor of disability.
Another way to operationalise frailty is by considering it as a state and counting in an individual the number of deficits that he/she has accumulated from a given list (of usually 30 or more potential deficits). Deficits are widely defined as symptoms, signs, diseases and disabilities that accumulate with age. The number of counted deficits divided by the number of deficits considered results in a score called frailty index (FI), which ranges from 0 (none of the deficits present) to 1 (all deficits present).
Frail older people have been underrepresented in clinical trials, and the incorporation of frailty metrics into future trials may facilitate the development of clinical guidelines that will be tailored to the biological age or frailty status of older persons.
The identification of frailty is, and will always be, an indication for Comprehensive Geriatric Assessment (CGA), which is the ‘gold standard’ interdisciplinary diagnostic process that will reveal the medical and psychosocial drivers of frailty that are potentially remediable. Frailty screening, as an age-independent marker of risk that fits the biopsychosocial model of primary care, may promote equity of access to CGA services (i.e. by giving quicker access to those in greater need).
In summary, once implemented in clinical practice, the new science of frailty will promote more equitable access to specialist geriatric services and more patient-centered, personalised treatment approaches.
This article is part of our week of blogs focussing on frailty, to mark the launch of new guidance Fit for Frailty.