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 to Frailty

Frailty is a clinical state that is associated with an increased risk of falls, harm events, institutionalisation, care needs and disability/death. It affects quality of life and is becoming more common with ageing populations. While it is generally accepted that frailty exists, it remains difficult to define and measure as it manifests differently in each individual. However, a working definition of frailty is as follows: it is a distinct clinical entity from ageing, but it is related to the ageing process. It consists of multi-system dysregulation leading to a loss of physiological reserve. This loss of reserve means that the individual living with frailty is in a state of increased vulnerability to stressors meaning they are more likely to suffer adverse effects from treatments, diseases or infections. Morley et al (2013) also provide the following definition:

“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.”

These are fairly complex definitions, but they can ultimately be broken down into two key concepts:

• Frailty is a distinct process separate from aging, but related to aging. While older people tend to be more frailty, you will not be frail just because you are old. Frailty depends on your physiological state and how well you can respond to stressors (injury/illness).
• Frailty involves multiple systems rather than just a single body system. Frail individuals will usually have a number of co-morbidities (eg cardiovascular, musculoskeletal and neurological).

Frailty is a dynamic state - there is evidence that frailty could be modifiable and has greater reversibility than disability. An individual's frailty level can be influenced by an intervention or lack of intervention. Overall, if unmanaged, a frail individual will follow a trajectory towards death and disability. It is estimated that 25% to 50% of individuals aged over 85 years are frail, but equally this means that up to 75% of people aged over 85 may not be frail. Importantly, up to three quarters of people over 85 years might not be frail, so as Clegg et al (2013) note, it is important to consider why some individuals become frail and how it might be detected and prevented.

Models of Frailty

There are two main theories of frailty: Fried's Phenotpye Model and Rockwood's Accumulation of Deficits Model. It is important to understand that these are not competing models. They should be considered as complimentary - both have been validated and have been used to develop various assessment tools and treatment indicators. In some instances, one model will work better than the other. For instance, Fried's model is particularly useful when assessing an individual who is who is pre-frail whereas Rockwood's model is more useful when assessing how cognitive issues may be impacting frailty.

Fried's Phenotype Model

Fried's Phenotype Model was first published in 2001. It is a yes-no model based on five sub categories. Each subcategory will be scored as 0 (no) or 1 (yes). It assumes an individual is frail if s/he has a score of greater than three. The five categories are:

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 (NB 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

The scoring is as follows: 0-1 = not frail 1-2 = pre-frail 3+ = frail (mild, moderate and severe)

When using this model, it is important to remember that frailty is a multi-system dysregulation. If an impairment is clearly due to a mono-articular or single system problem (eg low grip strength following a hand injury) then this must be considered when assessing for frailty. It should be noted also that this model focuses solely on physical attributes of frailty. Some therefore consider that it is an incomplete model as it does not address cognitive aspects or chronic conditions which are associated with frailty. However, this focus on physical attributes makes Fried's Model useful for physiotherapists as, it provides clear direction when creating treatment plans to address frailty - for instance if a patient is shown to have low muscle strength, treatment would focus on strengthening. Similarly patients who are found to be physically inactive would need to increase their activity levels.

Rockwood's Accumulation of Deficits Model

The Rockwood model considers how frailty can be the result of an accumulation of a number of deficits. This model shows that as people age, they develop health deficits - the more health deficits, the greater the risk. Not all adults develop the same number of deficits, so some become frail, whereas others do not. This accumulation of deficits can be quantified using the Frailty Index. Initially, 92 baseline parameters of symptoms, signs, abnormal laboratory results, disease states and disabilities - ie deficits - were used to define frailty. This has subsequently been reduced to around 30 variables. A patient's Frailty Index score indicates how many deficits are present - the more deficits, the greater the chance an individual is frail. The Frailty Index score is calculated through the (total number of impairments in the individual)/ (the total number of impairments examined). This model dichotomises each variable - you either have the deficit or you do not. An individual is considered more frail the closer their overall score is towards 1.0. Several studies have found that Frailty Index score is strongly related to the risk of death and institutionalisation.

Rockwood's Clinical Frailty Scale. 1-9 1 being not frail and 9 being temrinally ill.

The Frailty Index is considered a useful model for primary care (GPs or Geriatricians), but given it can be time consuming to complete, additional measures have been developed:

• The electronic frailty index (eFI) was developed by Clegg and colleagues in 2016. It identifies frailty using data that is held on primary care databases. It categorises patients into four categories based on this data: fit older individuals, as well as individuals with mild frailty, moderate frailty and severe frailty.
• The Clinical Frailty Scale is a straightforward and accessible tool that can be used to quickly and simply assess frailty (see image). It has been validated in adults aged over 65 years. A score from 1 (very fit) to 9 (terminally ill) is given based on the descriptions and pictographs of activity and functional status provided. Particular attention should be payed to those who score 5 or more as this is the marker for requiring a comprehensive geriatric assessment and often referral to geriatric or frailty specialists, A 2017 Cochrane review found that older people are more likely to be alive and in their own homes at follow-up if they received CGA on admission to hospital.

Conclusions

Both theoretical frameworks can be referenced and are valid in the literature. Fried’s criteria focusses solely on the physical aspects of frailty whereas Rockwood considers other deficits and chronic conditions.