Geriatrics
Clinical Frailty Scale (Rockwood)
Degree of frailty in older adults.
Education and reference only. Not a substitute for clinical judgement, local policy or product labelling. Always verify before clinical use. Values are calculated in your browser and never stored.
Background
The Clinical Frailty Scale (CFS), developed by Rockwood and colleagues, is a 9-point global measure that summarises a person's overall fitness or frailty based on clinical judgement of their function in the two weeks before any acute illness. It runs from 1 (very fit) through 4 (living with very mild frailty) and 5–8 (mild to very severe frailty) to 9 (terminally ill). It draws on mobility, energy, activity and dependence for daily and instrumental activities. It is a judgement-based summary, not a questionnaire, and is intended for use in people aged roughly 65 and over.
Interpreting the result
Levels 1–3 describe people who are fit; 4–6 span vulnerability through to moderate frailty with increasing need for help with daily activities; and 7–9 indicate severe frailty, complete dependence or the end of life. Higher levels are associated with worse outcomes from acute illness, surgery and critical care, and the scale is used to support shared decisions about the intensity of treatment. It should describe the baseline state before the acute event, not the patient at their sickest.
Advice
Use as part of a holistic assessment, not in isolation, and avoid using it alone to make resource-allocation decisions.
Worked example
An 84-year-old who needs help with shopping, finances and heavy housework but manages personal care and walks indoors with a stick scores around 5 (mild frailty). This vulnerability is taken into account when discussing the likely benefits and burdens of escalation, surgery or intensive care.
Pearls / pitfalls
- Score the baseline from before the acute illness — scoring the patient at their most unwell overestimates frailty.
- It is not validated for younger adults or for people whose disability is stable and longstanding (for example a young person with a learning disability or chronic neurological condition).
- It must never be used in isolation to deny treatment or allocate resources; it informs, but does not replace, individualised assessment and discussion.
- Cognitive impairment is captured indirectly through its effect on function, so corroborate with a collateral history.
Evidence & validation
The scale was validated in the Canadian Study of Health and Aging, where higher levels predicted death and institutionalisation. It is widely used in geriatric medicine and was incorporated into UK critical-care escalation guidance during the COVID-19 pandemic, though always as one component of holistic assessment.
Frequently asked questions
What time period should the CFS describe?
It should reflect the person's usual state in the two weeks before the current acute illness, not how they appear when acutely unwell. Scoring the sickest moment overestimates frailty.
Is the Clinical Frailty Scale suitable for younger adults?
No. It was developed and validated in older people, generally aged 65 and over, and is not appropriate for younger adults or those with stable lifelong disability.
Can the CFS be used to decide who gets intensive care?
It can inform a shared, individualised decision but must never be used alone to allocate resources or withhold treatment. It is one part of a holistic assessment.
How does the CFS handle dementia?
Cognitive impairment is reflected through its impact on day-to-day function rather than a separate question, with broad correspondence between dementia severity and CFS level. A collateral history helps.
What does a score of 9 mean?
A score of 9 denotes a person who is terminally ill, with a life expectancy of under about six months, who is not otherwise living with severe frailty. It sits at the end-of-life end of the scale.
References
- Rockwood K, Song X, MacKnight C, et al. A global clinical measure of fitness and frailty in elderly people. CMAJ. 2005;173(5):489–495.
- NICE NG159: COVID-19 rapid guideline: critical care in adults. 2020 (CFS use in escalation decisions).
About the creator
Rockwood K et al.
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