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Clinical Frailty Scale

Editor: Rafay Latif Updated: 4/23/2023 1:23:34 AM


Across the globe, the geriatric population is increasing, making frailty a concern of increasing importance for healthcare systems. Frailty is a multidimensional geriatric syndrome associated with poor health outcomes and will continue to place a substantial and increasing burden on healthcare systems.[1] Frailty represents a decreased physiologic reserve and function that is more prevalent with increasing age. It is characterized by increasing vulnerability to physiologic stressors.[2] 

Frailty is the result of cumulative cellular damage from diverse etiologies over the life of the individual—typical aging results in loss of homeostatic reserve in physiological systems. However, despite the loss of these reserves, many individuals still function well with aging. Any stress or insult to these physiologic reserves can result in an older adult decompensating and thus causing increased frailty. Patients can be categorized as robust, pre-frail, or frail, depending on the degree of physiological and functional decline.[3]

Frailty can develop due to factors such as (i) socio-demographic influences (e.g. poverty, living alone, low education level); (ii) psychological factors (e.g. depression); (iii) nutritional issues (e.g. malnutrition); (iv) polypharmacy; (v) diseases and complications (inflammatory states, cancer, endocrine disorders, dementia); and (v) low physical activity.[4] Despite the importance of frailty, there is currently no internationally recognized standard definition due to its complex etiology and the inherent difficulty in distinguishing frailty from both aging and disability. Irrespective of definitions, it is clear that frailty is an important geriatric syndrome, which is dynamic, fluctuates over time, and reflects multisystem dysfunction. Given its importance, since the mid-1990s, frailty scores have been developed to help quantify the degree of disability from frailty.[5]


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Frailty measures are an essential tool for use in clinical practice to help develop specific interventions and treatment plans accounting for the increased risk of adverse outcomes associated with frailty. Over the years, several instruments for assessing frailty have been developed.

One commonly used frailty assessment tool is the Clinical Frailty Scale (CFS). The CFS is a well-validated scale that evolved from the Canadian Study of Health and Aging and is frequently used in clinical settings. It provides a summary tool for clinicians to assess frailty and fitness based on their clinical judgment and evaluation of a patient. It was initially created with a scale from 1 (very fit) to 7 (severely frail) upon initial publication in 2005.[6] In 2007, however, the CFS was modified to a 9-point scale to include very severely frail and terminally ill as separate entities, which initially were lumped together. The CFS was updated again in 2020 with clarifying edits to the description and labels of the various levels of frailty. The severity of frailty increases with each numbered level, and there is a visual chart to assist with the frailty classification.

Applying the Clinical Frailty Scale to patients requires clinical judgment on the part of the examining clinician and thus may be subject to inter-observer variation. Although the CFS is touted as a quick and easy test, it does require data collection beyond that which could be collected by a cursory evaluation. It is heavily weighted on assessing patient function and includes a patient's ability to mobilize as well as inquiring about their habitual physical activity and abilities. It requires the clinicians to assess if the patient can independently perform tasks such as bathing, dressing, housework, going upstairs, going out alone, going shopping, taking care of finances, taking medications, and preparing meals. The main advantage besides its validity is that it is easy to use and may readily be administered in a clinical setting. The CFS is utilized to predict the outcomes of older people hospitalized with acute illnesses.[7] It has also been used to help predict in-patient mortality and thus help target specialty geriatric resources within the hospital.[8] 

Technique or Treatment

Clinical Frailty Scale Components

  1. Very Fit: People who are robust, active, energetic, and motivated. These people commonly exercise regularly. They are among the fittest for their age.
  2. Well: People who have no severe disease symptoms but are less fit than category 1. They exercise or are very active occasionally, e.g., seasonally.
  3. Managing Well: People whose medical problems are well-controlled but are not regularly active beyond routine walking.
  4. Living With Very Mild Frailty: Previously named "Vulnerable," While not dependent on others for daily help, symptoms often limit activities. A common complaint is being "slowed-up" and being tired during the day.
  5. Living with Mild Frailty: These people usually have more evident slowing and need help in higher-order instrumental activities of daily living (IADLs) such as finance, transportation, heavy housework, and medication management. Typically, mild frailty progressively impairs shopping and walking outside alone, meal preparation, and housekeeping.
  6. Living With Moderate Frailty: People need help with all outside activities and housekeeping. Inside often have problems with stairs, need help with bathing, and may need minimal assistance with dressing. 
  7. Living With Severe Frailty: Completely dependent for cognitive and physical personal care. However, they seem stable and not at high risk of dying (within six months).
  8. Living with Very Severe Frailty: Completely dependent for personal care and approaching end of life. Typically they could not recover even from minor illnesses.
  9. Terminally Ill: Approaching the end of life. This category applies to people with a life expectancy of under six months who are not otherwise living with severe frailty. (Many terminally ill people can still exercise until very close to death.) 

Scoring frailty in a patient with dementia: The degree of frailty corresponds to the degree of dementia. Common symptoms in mild dementia include forgetting the details of a recent event, though still remembering the event itself, repeating the same question/story, and social withdrawal. In moderate dementia, recent memory is significantly impaired, even though they seemingly can remember their past life events well. They can do personal care with prompting. In severe dementia, they cannot do personal care without help. In very severe dementia, they are often bedfast; many are virtually mute. 

Clinical Significance

The diagnosis of frailty frequently poses a diagnostic dilemma.[9] Despite the importance of frailty, there is currently no internationally recognized standard definition due to its complex etiology, varied definitions used by researchers, and the inherent difficulty in distinguishing frailty from aging and disability. Several frailty scores have been developed, combining multiple manifestations of frailty. Some alternative scales that have been utilized and studied include the Frailty Phenotype (FP), the 5-Item Frailty Trait Scale (FTS-5), and the Survey of Health, Aging, and Retirement Frailty Index (SHARE-FI), among others. Studies have not shown a high correlation between the different scales, possibly because they evaluate different manifestations or types of frailty. Some focus on function, such as the ability to perform activities of daily living independently. In contrast, others include objective measures such as unintentional weight loss or subjective symptoms such as self-reported exhaustion.[10]  

The Clinical Frailty Scale (CFS) is a prominent, well-validated, and frequently used score among these options. It is heavily weighted to evaluate function, including the ability to mobilize and perform activities of daily living. It helps identify those patients at risk for adverse outcomes due to frailty and can help providers implement timely preventive strategies to maximize patient outcomes.[11] The CFS has shown high accuracy as well as feasibility when implemented in the clinical setting.[12] 

Recent studies have shown that increasing scores on the Clinical Frailty Scale are linearly correlated with increased mortality in patients with COVID19 infections.[13] The clinical frailty score can also be useful in triage, as higher scores have been shown to be predictive of adverse outcomes in patients evaluated in the emergency department.[14] The CFS has been utilized in many care settings, including nursing homes, the intensive care unit, during emergency room and hospital admissions, and preoperative evaluations.[15][12]

Criticisms of the clinical frailty scale have pointed out that due to it being heavily weighted on patient function, it can be susceptible to an inherent "ableism" bias. For example, a patient with a congenital or traumatic amputation may require a similar level of in-hospital care as a patient with an amputation due to poorly controlled chronic diabetes. The first may be of greater baseline health status than the latter. There is concern that using the Clinical Frailty Scale to allocate limited medical resources, such as those in the ICU, may be negatively influenced by an "ableist" bias.[16]

Enhancing Healthcare Team Outcomes

Integrating frailty measures in clinical practice is crucial for developing interventions and individual care plans accounting for age-related conditions (particularly disability) in older persons. Multiple instruments have been developed over the years to capture frailty. The clinical frailty scale is a 9-point scale that quantifies frailty based on function in individual patients. It is complemented by a visual chart to assist with the classification of frailty. Higher scores indicate increased frailty and associated risks. The scale is well validated and has been tested in various clinical settings.[Level 1] This scale can be used by an interprofessional healthcare team of clinicians, including physicians, physician assistants, nurse practitioners, nurses, pharmacists, and nutritionists, to classify frailty and identify patients at high risk for adverse outcomes.[17] This tool can help optimize quality of life outcomes for geriatric patients.

*Kenneth Rockwood has given signed permission to use CFS for StatPearls use.



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Level 2 (mid-level) evidence


Dunne MJ, Abah U, Scarci M. Frailty assessment in thoracic surgery. Interactive cardiovascular and thoracic surgery. 2014 May:18(5):667-70. doi: 10.1093/icvts/ivt542. Epub 2014 Jan 27     [PubMed PMID: 24473474]


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Level 2 (mid-level) evidence


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Level 2 (mid-level) evidence


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Level 1 (high-level) evidence


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Level 1 (high-level) evidence