Introduction to Frailty

Original Editor - Christina Nowak Top Contributors - Jess Bell, Kim Jackson, Scott Buxton, Lucinda hampton, Lauren Lopez, Tony Lowe, Tarina van der Stockt, Admin, Christina Nowak and Shaimaa Eldib

Introduction

Frailty is difficult to define as it manifests differently in each individual and therefore there is some debate about the definition of frailty. The best way to summarise what frailty is is by using this definition: frailty is a distinct clinical entity from aging but related to the aging process consisting of multi-system dysregulation leading to a loss of physiological reserve. This loss of reserve means the individual living with frailty is in a state of increased vulnerability to stressors meaning they are more likey to suffer adverse effects from treatments or other diseases or infections. Succinctly this can be said:

“Frailty is a clinical state in which there is an increase in an individual’s vulnerability for developing increased dependency and/or mortality when exposed to a stressor.”

When clinicians come across the concept of frailty for the first time it is often intuitively understood as we can universaly accept when someone looks frail or not. But if we look a little deeper questions start to arise such as how do we differentiate between being frail and not frail and If frailty manifests differently between individuals how do we record this? To answer these questions we need to understand the theory and pathophysiology of frailty and there are two main theories: Freids Phenotpye Model and Rockwoods Accumulation of Defecits Model. It is important to understand that these are not competing models consider them as complimentary as both have been validated and have gone on to evolve into different assessment tools and treatment indicators. You may want to use each model in different settings and for different patient groups. For example Fried's model is particularly good for assessing someone who is pre-frail and Rockwoods is better at incorporating cognitive disorders within someones frailty.

Freid's Phenotype Model

As a physiotherapist you may find this model more intuitive as you can use familiar outcome measures within each of the 5 sub categories. Each subcategory will give you a 0 or 1 score (0 being no and 1 being yes).

Fried’s framework outlines five criteria related to labelling a person as frail.
These include:

1. Physical Inactivity - measured using the usual outcome measures you would expect
2. Low muscle strength - can be measured in grip strength ^{(<21kgf in men and <14 kgf in women however this is dependent on ethnicity)}
3. Slow gait speed - less than 0.8 m/s with or without a walking aid
4. Exhaustion/ fatigue - this is self-reported
5. Weight loss - loss of 10lbs or more in 1 year

0-1 = not frail 1-2 = pre-frail 3+ = frail (mild, moderate and severe)

Clearly these methods of measuring frailty in high levels of accuracy is flawed because someone who is not frail might have low grip strength due to a prior injury or condition and the same can be said for each criteria. This is why remembering that frailty is a multi-system dysregulation is essential. If you can clearly rule out something because of a mono-articular or single system problem then this must be considered. This is the reason the estimated prevalence of people living with frailty in different countries and within sub-sets of population can vary drastically .

This framework focusses solely on the physical attributes of frailty therefore there is an argument for saying this model is incomplete as it does not address cognitive aspects or chronic conditions which are associated with frailty .

Rockwood's Accumulation of Deficits Model

The Accumulation of Deficits approach considers the number of conditions present in the individual and gives the person a score of 0 to 1 known as the Frailty Index. The score is calculated through the (total number of impairments in the individual)/ (the total number of impairments examined). Conditions range from diabetes, visual issues, to mental health concerns and difficulties with mobility around the house. This model dichotomizes each variable, you either have the condition or you do not. The higher your score towards one, the more frail you are considered with the presence of 8-9 issues being the cut off number for frailty (0.3)⁵.

Epidemiological studies has shown that this Frailty Index has a high predictive ability for mortality in both men and women.

Conclusions

Both theoretical frameworks can be referenced and are valid in the literature though work is being done to create a unified picture of frailty to ensure proper execution of research related to frailty. Fried’s criteria focusses solely on the physical aspects of frailty whereas Rockwood considers other deficits and chronic conditions.