Frailty: joining the giants.

Since Isaacs made that statement, further giants of geriatric medicine, such as iatrogenesis, have been added to the list. The concept of geriatric syndromes has been universally accepted with internationally agreed-upon definitions and numerous guidelines for assessment and treatment. The last decade has seen a burgeoning interest in yet another giant: the frailty syndrome. Frailty can be thought of as a combination of factors that influence a person’s physiologic state to the extent that function is greatly reduced and the person becomes more vulnerable to external stressors. This vulnerability can result in disability, admission to hospital or a long-term care facility and increased risk of death. Although the concept of frailty is generally accepted (despite the pejorative connotations of the term “frail”), its definition is not. Separate models by Fried and Rockwood are often cited and have been employed in clinical trials. In Fried’s model, the presence of three or more of five indicators (unintended weight loss, tiredness, weak grip strength, slow walking speed and physical inactivity) predicts a range of adverse outcomes including falls, disability, admission to hospital and death. Fried and colleagues stated that frailty was distinct from comorbidity and disability, although the categories did overlap. Although the “diagnosis” of frailty using defined cutoff values is attractive, the Fried criteria are difficult to apply to all groups, such as those patients who are acutely ill and the most dependent. Various amendments to the Fried criteria have been suggested by other investigators. A fairly recent study attempted to produce an instrument for identifying frailty among patients at primary care institutions in Europe, which the authors claimed was a valid alternative to the Fried model. The Fried criteria do not specifically include direct measurements of mental health or psychosocial status, measures that clinicians and older people alike feel are an important part of the definition of frailty. In fact, more recently, Fried and coauthors suggested that these factors were related to frailty. An alternative model that took a quantitative approach and defined frailty as the accumulation of deficits was suggested by Rockwood and coworkers. They proposed that the risk of becoming frail increased with certain deficits. These deficits may be multisystem physiologic or cognitive changes (not necessarily diseases) that can be seen in clinical data. The deficits exist on a continuous scale and can be indexed. Thus, the more deficits that are present, the higher the index and the greater the risk that the patient will become frail. Unlike the Fried criteria, the Rockwood model can incorporate the patient’s mental health or psychosocial status. Rockwood has further developed the concept of accumulated deficit in a paper published in this issue of CMAJ, in which he showed that the number of deficits predicted mortality across the adult lifespan, although the prevalence of frailty was much lower in younger patients. However, this model has not been fully accepted in the clinical setting, possibly because of its complexity. Rockwood and colleagues tried to address this problem by introducing a sevenpoint clinical scale for measuring frailty. This scale is judgment-based and asks the clinician to evaluate a patient’s fitness, wellness, comorbidity and three levels of frailty based on dependency. Evidence that these two approaches may share certain similarities comes from a further analysis of the Womens’ Health and Aging Studies. These prospective, observational studies Frailty: joining the giants