Empowering Self-assessment of Frailty: A Revised CFS-Self Tool for Primary and Community Care
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Dear Editor,
Frailty is a syndrome in which homeostatic compromise across multiple body systems increases one’s vulnerability to adverse outcomes such as morbidity and mortality.1) Its prevalence is expected to rise with an ageing population, necessitating early detection and interventions to mitigate its impact.2) In response, the Healthier Singapore initiative, launched by Singapore Ministry of Health in 2022, aims to promote preventive health through partnerships with primary and community care providers.3) As part of its phased implementation, the initiative will integrate frailty screening with secondary assessments and interventions into its care protocols. To support this, the Singapore National Frailty Policy Workgroup has recommended the Clinical Frailty Scale (CFS) as the national frailty screening tool.2)
The CFS is a validated, judgement-based tool that categorizes individuals from 1 (very fit) to 9 (terminally ill), based on fitness level, physical activity, functional status, and cognitive ability.4) It is widely used for its simplicity and potential for algorithm-guided scoring to increase the accuracy of CFS rating.5,6) The CFS’s graded structure allows for effective staging of frailty severity, enabling tailored follow-up assessments and efficient allocation of healthcare resources.2) However, a key limitation is its requirement for a trained assessor, which may hinder large-scale screening and population-level monitoring.6,7)
To overcome this, the CFS-Self was developed for self-administration8) and it has been validated against the Frailty Index with good diagnostic accuracy and predictive ability for adverse outcomes in the emergency setting.9) It is a 4-item self- or caregiver-administered questionnaire evaluating basic activities of daily living (bADLs: toileting, dressing, showering, and walking); instrumental activities of daily living (iADLs: going outside, managing finances, and medication adherence); fatigue (“feeling constantly tired throughout the day”); and slowing of gait (“walking slower than usual”). Individuals are categorized as: CFS 1–3 (robust), CFS 4 (very mildly frail), CFS 5 (mildly frail), CFS 6 (moderately frail), and CFS 7–8 (severely frail).
Subsequently, a team of primary care physicians and geriatricians revised the CFS-Self for use in community and primary care settings. The revised CFS-Self incorporated 4 modifications to the original version. (Supplementary Figs. S1 and S2) Firstly, a fifth question on “physical activity beyond routine walking” was added to distinguish CFS 1–2 from CFS 3. From a primary care perspective, as physical inactivity is a significant modifiable risk factor for frailty,10) individuals at CFS 3 may be amenable to early intervention aimed at increasing physical activity. Secondly, the fatigue question was reworded to “feel tired more easily” to better align with Rockwood and Theou’s 2019 CFS guide.4) Thirdly, the format and pictorial aids of the questionnaire were enhanced based on feedback from six patient interviews, with the goal of improving readability and comprehension. Lastly, a Chinese version of the revised CFS-Self was developed alongside the English version, reflecting the two most widely spoken languages in Singapore.11)
A pilot study was conducted in the primary care setting to assess the agreement between self-administered ratings (revised CFS-Self) and the “gold standard” assessor-administered ratings by trained care coordinators (CFS-CC). These care coordinators, while not clinicians, were trained to assess frailty using CFS as part of their role in promoting preventive health services. In this study, to minimise bias, the care coordinators completed the CFS-CC independently before instructing patients to complete a self-administered questionnaire outside the consultation room. The questionnaire included the CFS-Self, items on sociodemographic characteristics and a 5-point Likert scale to gauge the ease of use of the CFS-Self. Patients were instructed to place the completed questionnaire in a collection box outside the room without further explanation, ensuring that the process remained fully self-administered. Inter-rater agreement was analysed using quadratic-weighted kappa statistics with bootstrapping and bias-corrected and accelerated confidence intervals to account for sparse data. This study was conducted as part of a clinical service improvement initiative and was exempt from ethics approval.
Of the 112 patients assessed, two were excluded due to incomplete responses. The mean age of participants was 73.7±6.0 years, and slightly more than half were female (n=59, 53.6%). The majority were Chinese (n=104, 94.5%), and most had secondary education or below (n=90, 81.8%). CFS-CC ratings ranged from 1 to 5, while CFS-Self ratings spanned from 1 to 7–8 (Table 1).
Comparison of CFS-Self against CFS rated by care coordinators (CC) using 6 and 4 categorizations
We adopted two approaches to group the CFS scores: the original 6-category classification of the CFS-Self (CFS 1-2, CFS 3, CFS 4, CFS 5, CFS 6, CFS 7-8), and a simplified 4-category grouping based on expected interventions—CFS 1-2 (very fit/fit), CFS 3 (not physically active), CFS 4-5 (very mild/mild frailty), and CFS 6–8 (moderate/severe frailty). The weighted kappa was 0.608 (95% confidence interval [CI], 0.479–0.717) for the 6-category grouping with highest concordance in CFS 1-2 (78.8%) and lowest in CFS 5 (0%), CFS 6 (0%), and CFS 7-8 (0%). In comparison, the 4-category grouping yielded a weighted kappa of 0.668 (95% CI, 0.545–0.770), with concordance highest in CFS 1-2 (78.8%) and lowest in CFS 6-8 (0%). Most participants (n=68, 61.8%) rated the revised CFS-Self as “easy” or “very easy” to use. A smaller proportion (n=18, 16.3%) rated it as “difficult” or “very difficult,” while the remaining (n=24, 21.9%) were neutral.
Our findings demonstrated the potential utility of the revised CFS-Self for large-scale initial frailty screening in community and primary care settings where majority of older adults are robust to mildly frail.2) More than two-thirds of participants found the tool easy to self-administer and there was moderate agreement between the CFS-Self and CFS-CC, especially among patients rated CFS 1 to 4. The low concordance between the CFS-Self and CFS-CC in frailer patients (CFS 5 to 8) may be attributed to the care coordinators’ non-clinical background and the relatively small study sample with very few frail individuals. As their work primarily involves the identification of older persons with low physical activity or very mild frailty (CFS 3-4) for early intervention, the care coordinators may be less familiar with assessing the deficits in bADLs and iADLs which are associated with higher frailty states. This may have affected the accuracy of the assessor-administered CFS ratings and is a major limitation restricting the generalizability of our findings to frailer populations.
Despite the study limitations, the CFS-Self shows promise as a feasible large-scale frailty screening tool compared to established instruments such as the FRAIL scale,12) another 5-item self-reported tool that categorizes individuals into robust, pre-frail and frail states. While the CFS-Self is similarly easy to administer, it’s nuanced ratings across a frailty continuum allow for more precise understanding of an individual’s frailty status. This can better guide patient care, develop health policy and optimize healthcare resources.2) To inform implementation, future work should evaluate the agreement between CFS-Self and clinician-rated CFS among older adults ranging from robust to very frail older adults in community-based active ageing centres and other healthcare facilities. Additionally, it is important to include proxy-respondent (caregiver)-administered CFS-Self assessments, especially among frailer populations with visual or cognitive impairment, where caregiver input may be necessary. Understanding the agreement between the CFS-Self and CFS across a diverse population from different settings and identifying the factors associated with rating discrepancies is crucial for refining strategies for population-level frailty screening using self-administered tools.
Notes
We express our deepest gratitude to Dr Edward Chong, Prof Christian Apfelbacher, Dr Vaingankar Janhavi Ajit, Dr David Ng and Dr Sabrina Poay Sian Lee for their invaluable contributions to the revision of the CFS-Self; Dr Lye Yoong Tan, Ms Doreen Wai Peng Chan, Ms Nur Iffah Binte Abdul Halim, Ms Li Ping Ang, Ms Priscilla Xin Hui Lim, Ms Fadzlina Binte Sujak, and Ms Jessica Koh for their assistance in conducting the study at Toa Payoh Polyclinic, and Ms Jie Chi Wong for her support with data entry.
Generative AI tool was used to improve the readability and language of this manuscript.
CONFLICT OF INTEREST
The authors claim no conflicts of interest.
FUNDING
The work was supported by National Healthcare Group Translational Research Program Funding.
AUTHOR CONTRIBUTIONS
Conceptualization, SZS; Methodology, SZS, WSL; Investigation, WCG, DZ; Formal analysis, XN; Writing-original draft, SZS; Writing-review and editing, SYT, WSL, ESL.
SUPPLEMENTARY MATERIALS
Supplementary materials can be found via https://doi.org/10.4235/agmr.25.0076.
CFS-Self questionnaire.
Clinical frailty Scale.