Now that we have a definition for physical frailty, what shape should frailty medicine take?

摘要

Concepts of frailty sit at the heart of much current discourse about how we deliver and develop services for vulnerable older people. Yet the word frail is used variably and imprecisely. Some of this might be attributable to the differences between lay and technical definitions, but there has also been a failure within the scientific literature to agree a core specification of 'what is frail'. Two main theoretical constructs have come to dominate the conversation. Fried et al.'s phenotypic model defined a constellation of five possible components (weight loss, exhaustion, weakness, slowness and reduced physical activity), which indicate an underlying physiological state of multisystem dysregulation 1. Rockwood and Mitnitski, meanwhile, described an accumulation of deficits model, which counted the number of impairments and conditions in an individual patient to create a Frailty Index 2. These models demonstrate a degree of overlap and statistical convergence in terms of their ability to predict adverse outcomes but they, nevertheless, identify different patient cohorts as frail 3. This has led to tension about which ought to be operationalised in clinical practice.