Across the globe, in all countries, the number of older adults is increasing. These increases in the elderly population are making frailty an increasing concern for the healthcare system. Frailty is a multidimensional geriatric syndrome, which is characterized by an increased vulnerability to various external stressors. Frailty is associated with multiple adverse outcomes, including mortality, admissions to nursing homes, and falls. It will continue to place a substantial and increasing burden on public health and healthcare systems.[1]

Frailty is the result of cumulative cellular damage from diverse etiologies over the life of the individual. Typical aging results in loss of some homeostatic reserve in physiological systems. However, despite the loss of these reserves, individuals still function well with aging. Any homeostatic perturbation in these reserves will result in the older adult decompensating and thus causing frailty. The silent precursor to frailty is pre-frailty or latent frailty. Frailty happens from latent frailty whenever external stressors (e.g., acute illness, injury, or mental stress) occur in the older adult.[2]

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.[3] Despite the importance of frailty, there is currently no internationally recognized standard definition given its complex etiology; definitions used by different frailty researchers; 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 combination scores have been developed, wherein a constellation of frailty manifestations was grouped to be able to quantify the degree of disability from frailty.

Frailty measures are essential to include in clinical practice so one can develop various interventions for resulting disability for older adults. Over the years, several instruments for assessing frailty are in use.

One of the scales commonly used is the Clinical Frailty Scale (CFS).[4] The CFS is a validated scale. It evolved from the Canadian Study of Health and Aging. Since its publication, the CFS is in frequent use in clinical settings. It provides a summary tool for clinicians to assess frailty and fitness. The elements are derived based on the clinician’s clinical judgment. It was scored on a scale from 1 (very fit) to 7 (severely frail) upon initial publication in 2005. 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 9-point scale provides a descriptor of a frailty stage. There is a visual chart to assist with the frailty classification. A person with a score ≥of 5 is considered frail.

Applying the CFS to patients requires clinical judgment on the part of the examining clinician and thus may be subjected 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 does entail watching the patient (mobilize), inquiring about their habitual physical activity and ability. 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.[5] It has also been used to help predict in-patient mortality and thus help target specialty geriatric resources within the hospital.[6] 

One of the limitations of this scale is that it combines several domains of frailty and disability and may not be as applicable as other phenotype-oriented frailty scales. The patient’s level of disability heavily weights the CFS. It is unclear if the CFS offers superior or redundant value in contrast to other disability scales (e.g., Katz Index).[7]