Frailty is an emerging geriatric syndrome [1
], and its associations include falls, disability, morbidity, mortality and excess healthcare costs from consultations, polypharmacy, hospitalisations and institutionalisations [2
]. Frailty confers loss of independence, vulnerability and impairs the quality of life and psychological well-being of many older people; it also poses an enormous challenge on families, carers and other structures of social care and social support. The prevalence of frailty in community-dwelling older Europeans (65 years and older) varies between 5.8% and 27.3%; in addition, between 34.6% and 50.9% are classified as 'pre-frail' [6
]. In the face of the rapid population ageing occurring in Western societies, frailty is set to reach epidemic proportions over the next few decades.
Frailty is an entity recognised by clinicians, with multiple manifestations and with no single symptom being sufficient or essential in its presentation [7
]. In part due to its syndromic nature, and despite considerable research efforts in the field, an operational definition of frailty that meets international consensus is still lacking [8
]. Defining frailty requires a complex systems
] and, in general, it is accepted that a good definition should not only capture the biological
, but also the psychosocial
correlates of frailty [14
]. In addition, it has been suggested that frailty could have a gendered dimension and manifest differently in males and females [15
Numerous frailty definitions and assessment tools have been developed in clinical practice and research, and this has been the focus of many reviews and comparative studies [3
]. In particular, Fried et al
.'s frailty phenotype
] has achieved international reputation. The method has been extensively validated in the research literature [23
]; however, a criticism is that it is not readily applicable in routine primary care practice.
The main advantage of Fried's method is that it requires the measurement of only five variables, namely weight loss
, grip strength
, walking speed
and physical activity
]. Whilst this is affordable from a primary care point of view, the problem arises with the construction of the measure. In Fried's definition, frailty is defined in terms of three categories, each of which is defined by the sum of the number of individual criteria present (0: non-frail
, 1 or 2: pre-frail
, and 3, 4 or 5: frail
). The dichotomisation of individual criteria that are measured on a continuous scale (i.e. grip strength, walking speed and physical activity) is done retrospectively according to the lowest twentieth percentile rule, and there are further stratifications. This requires considerable statistical expertise and also a reference sample, both of which are not always available to primary care practitioners.
With the ageing of the population in Western societies and the rising costs of health and social care, many countries are refocusing health policy on health promotion and disability prevention among older people. It has been argued that efforts aimed at identifying at-risk groups of older people in order to provide early intervention and/or multidisciplinary case management should be done at the level of general practice
via adoption of a clinical paradigm based on the concept of frailty, which fits well with the biopsychosocial model of primary care [26
]. However, this ideal has exposed the lack of frailty metrics that are appropriate for primary care. Indeed, family physicians and community practitioners are still in need of easy instruments for frailty [27
Recently, Santos-Eggimann et al.
employed an approach to Fried's method in the first wave of the Survey of Health, Ageing and Retirement in Europe (SHARE), in order to establish the prevalence of frailty in middle-aged and older community-dwelling Europeans living in ten countries [6
]. Since SHARE did not collect Fried's criteria according to their original definition, Santos-Eggimann et al.
selected the five SHARE variables that in their view were the closest to Fried's variables. Although their selection was not without significant departures from Fried's theoretical model, their effort represented the first-time attempt to operationalise Fried's frailty phenotype in a very large European population-based sample.
Building upon Santos-Eggimann et al
.'s work, and using methodology previously described by Bandeen-Roche et al.
on Fried's original variables [22
], the aims of this study were to assess whether those five SHARE variables approaching Fried's frailty phenotype had internal validity on their own
and could be statistically summarised in a single factor
with three underlying latent classes
(i.e. non-frail, pre-frail and frail), with appropriate biopsychosocial correlates and predictive validity.
Rather than replicating Fried's paradigm, our aim was to offer a valid related alternative to it in the European context, whist taking advantage of the unparalleled data resource made available by SHARE. The ultimate goal was to provide European community practitioners with a simple and valid instrument that offers a pre-calculated, population-representative and gender-specific frailty class, once the five measurements are entered. The SHARE Frailty Instrument (SHARE-FI) is intended to facilitate the rapid assessment of frailty in primary care and enhance the communication between the various agencies managing middle-aged and older people in the community.