Clinical Frailty Scale
The Clinical Frailty Scale (CFS) was introduced in the second clinical examination of the Canadian Study of Health and Aging (CSHA) as a way to summarize the overall level of fitness or frailty of an older adult after they had been evaluated by an experienced clinician (Rockwood et al., 2005).
Although introduced as a means of summarizing a multidimensional assessment in an epidemiological setting, the CFS quickly evolved for clinical use, and has been widely taken up as a judgement-based tool to screen for frailty and to broadly stratify degrees of fitness and frailty. It is not a questionnaire, but a way to summarize information from a clinical encounter with an older person, in a context in which it is useful to screen for and roughly quantify an individual鈥檚 overall health status.
The highest grade of the CFS (level 7) as published in 2005, incorporated both severe frailty and terminal illness. Later, it became evident that we needed to distinguish between identifiable groups who were otherwise lumped together in the original scale 鈥� severely frail, very severely frail and terminally ill - as clinically distinct groups who required distinctive care plans. Therefore, in 2007 the CFS was expanded from a 7-point scale to the present 9-point scale, and it has been used extensively in that format. We published on the predictive validity of the 9-point CFS in 2020 (Pulok et al., 2020).听
In 2020 the CFS was further revised (version 2.0) with minor clarifying edits to the level descriptions and their corresponding labels. Most notably, CFS level 2 changed from "Well" to "Fit", level 4 from "Vulnerable" to "Living with Very Mild Frailty", and levels 5-8 were restated as "Living with..." mild, moderate, severe, and very severe frailty, respectively (Rockwood & Theou, 2020).听
Please refer to the听CFS Guidance and Training听section below for more information and resources about using the Clinical Frailty Scale. We've also developed a听classification tree听to assist novice raters with CFS scoring:
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CFS Classification Tree
Scoring the Clinical Frailty Scale (CFS) requires clinical judgment. Increased uptake of the CFS internationally 鈥� bolstered by the recent COVID-19 pandemic 鈥� has led to the CFS being used by many health care professionals who do not have formal training in frailty care. While the CFS generally has very good inter-rater reliability, CFS scoring by inexperienced raters may not reflect expert judgment. We developed a classification tree听to simplify听use of听the Clinical Frailty Scale for novice raters.听
This classification tree is not intended to replace the CFS听or clinical judgement. It may not be useful to experienced CFS raters, but it can aid听in routine CFS scoring for inexperienced raters. Even so, raters using the classification tree should confirm whether their clinical judgement agrees with听the CFS score derived by听the classification tree. If the rater does not agree with the听CFS level proposed for their patient by the听classification tree, they should use clinical judgement to determine the appropriate CFS level. In听a prospective study of 115 older adults assessed in an emergency department, the level of frailty derived using the classification tree matched the CFS听score assigned by an experienced geriatrician in 63% of the cases; an additional 30% agreed within +/- one level听(Theou听et al., 2021).
The CFS classification tree can be听navigated听using routinely collected clinical data. If routine听data are not available, raters can use a questionnaire听we听developed to collect the data听needed听to navigate听the classification tree听and arrive at a CFS score.听The听听[PDF - 540KB] allows raters to听record听information听about specific听health conditions.听There is also a 听[PDF - 77KB] of the questionnaire听that听captures information about health conditions in aggregate听(e.g. the total number of听health听conditions).听Both versions assess听the same health domains.
In addition to the paper form, the questionnaire (in its full and short versions) can be accessed as an听听with the classification tree algorithm embedded. Using the online tool, users are prompted to respond to questions until the algorithm collects enough information to propose a CFS score. The online tool does not save or store data.
As a result of its worldwide uptake, the Clinical Frailty Scale is now available in a number of languages (see听Translations).听
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Training and Guidance
Guidance for using the听Clinical Frailty Scale听has been published in听.
Partnering with听, we developed the "Top Tips to help you use the Clinical Frailty Scale" as a resource for new or novice users of the CFS (see download links below image):
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听[PDF - 540 KB]
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Additional Resources
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References
Rockwood K, Song X, MacKnight C, Bergman H, Hogan DB, McDowell I, Mitnitski A.听听CMAJ.2005;173(5):489-495.
Pulok MH, Theou O, van der Valk AM, Rockwood K.听.听Age Ageing.听2020;49(6):1071-1079. 听
Rockwood K, Theou O.听.听Can Geriatr J. 2020:23(3):210-215.
Theou O, P茅rez-Zepeda MU, van der Valk AM, Searle SD, Howlett SE, Rockwood K.听Age Ageing. 2021;50:1406-1411.
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Permission for Use
To guard against copyright infringement or unlicensed commercial use, we ask all potential users to complete a听Permission for Use Agreement via the听online听Permission Request Portal.听Agreements are reviewed by the Industry Liaison Office at 鲍鱼tv University to determine whether a license agreement is required. Requests for non-commercial educational, clinical and research use, as well as for reprint usually do not require a license agreement.