Background
Main text
Controversies in frailty definition
Assessment tools to identify frailty
-
Frailty phenotype: Fried [8] defines a phenotype of frailty by the presence of three or more of the following components: shrinking, weakness, poor endurance and energy, slowness and low physical activity level. Presence of one or two deficits indicates a prefrail condition, while the absence of deficit indicates a robust state.
-
Strawbridge questionnaire: The questionnaire developed by Strawbridge in 1998 [27], defines frailty as difficulty in two or more functional domains (physical, cognitive, sensory, and nutritive).
-
Edmonton Frail Scale (EFS): The EFS samples 8 domains (Cognitive impairment, health attitudes, social support, medication use, nutrition, mood, continence and functional abilities). The maximum score is 17 and represents the highest level of frailty [28]. A score range between 0 and 3 defines a robust state, a score of 4 or 5 corresponds to the slightly frail state, a score range between 6 and 8 corresponds to the moderately frail state and a score range between 9 and 17 corresponds to the severely frail state.
-
Clinical Frailty Scale (CFS): CSF is based on a clinical evaluation in the domains of mobility, energy, physical activity and function. The scale uses descriptors, icons and figures to stratify older adults according to their level of vulnerability and the score ranges from 1 (robust health) to 7 (complete functional dependence on others) [17].
-
FRAIL Scale: The Frail Scale includes 5 components and considers deficits accumulated in these 5 domains, forming its acronym: Fatigue, Resistance, Ambulation, Illness, and Loss of weight. Frail scale scores range from 0–5 (i.e., 1 point for each component; 0 = best to 5 = worst) and represent frail (3–5), pre-frail (1–2), and robust (0) health status [29,30].
-
Groningen Frailty Indicator (GgugFI) : The GFI consists of 15 self-report items and screens for loss of functions and resources in four domains: physical, cognitive, social, and psychological. Scores range from zero (not frail) to fifteen (very frail). A score of GFI of 4 or higher is regarded as frail [31].
-
Share Frailty Instrument (Share-FI) : Using the five SHARE frailty variables (fatigue, loss of appetite, grip strength, functional difficulties and physical activity), DFactor scores (DFS) were determined using the SHARE-FI formula and based on the DFS value, the subject could then be categorized as non-frail, pre-frail, or frail [32].
-
Tilburg Frailty Indicator (TFI): The TFI consists of 2 parts. Part A contains 10 questions on determinants of frailty and diseases (multi-morbidity); part B contains 3 domains of frailty (quality of life, disability, and healthcare utilization) with a total of 15 questions on components of frailty. The cut off point for frailty is defined as 5 points [33].
-
Frailty index: The index is often expressed as a ratio of deficits present to the total number of deficits considered. It shows a consistent, sub-maximal limit at about 2/3 of the deficits that are considered. Frailty index includes 40 variables [34].
-
The Gérontopôle Frailty Screening Tool [35]: Two different parts compose the instrument that has been developed as a screening tool. The first one appears as a questionnaire. Its main objective is to attract the general practitioner’s attention to very general signs and/or symptoms potentially indicating the presence of an underlying frailty status. In the second part, the general practitioner expresses his/her own view about the frailty status of the individual.
Epidemiology of frailty
Screening frailty
Consequences of frailty
-
The Cardiovascular Health Study (CHS) showed a predictive association between frailty and intermediate frailty status with incident falls, worsened mobility or activities of daily living (ADL) disability, incident hospitalization and death over 3 or 7 years of follow up, with hazard ratio ranging respectively from 1.82 to 4.46 and from 1.28 to 2.10 for the frail and intermediate groups [8].
-
The Canadian Study of Health and Aging (CSHA) highlighted that increasing frailty was associated with an increased 5-year risk for death, with an odds ratio of 4.82 (95% CI: 3.74 - 6.21) among mildly frail people and 7.34 (95% CI 4.73- 11.38) among severely frail people. Moreover, in this study, frailty was the most important predictor of death and institutionalization (Odds ratio: 7.28 (95% CI 5.01-10.58) among mildly frail people and 8.64 (95% CI 4.92-15.17) among severely frail people) [53]. This study therefore shows that the risk for adverse health outcomes increased markedly with frailty and these risks persist after adjustments for age, sex, comorbid conditions, and poor self-rated health.
-
The Women’s Health and Aging Study (WHAS) showed, in agreement with analyses in the CHS, that frailty strongly predicted all considered outcomes except falls and first hospitalization. Indeed, compared to robust individuals, frail women had a 6-fold higher risk of death and a more than 10-fold higher risk of incident instrumental ADL (IADL) and ADL disability and nursing home entry [54].
-
The Study of Osteoporotic Fracture (SOF) showed that frailty was associated with increased odds of 2 or more falls in the subsequent year. Compared with robust women, women in the intermediate group had a 1.2- to 1.4-fold age-adjusted increase in risk (P < .04) and frail women had a 2.4-fold increase in risk (P < .001). Then, the odds of incident disability (≥1 new IADL impairment) were greater with increasing evidence of frailty. Compared with robust women, women in the intermediate group had an age-adjusted 1.8- to 1.9-fold increase in risk of disability (P < .001) and frail women had a 2.2- to 2.9-fold increase in risk of disability (P < .001). All-cause mortality rates were also higher with increasing evidence of frailty. Compared with robust women, women in the intermediate group had an age-adjusted 1.4- to 1.5-fold increased risk of death (P < .001) and frail women had a 2.4- to 2.7-fold increased risk of death (P < .001) [55].