Editorial: Something About Frailty

Abstract

FRAILTY is a commonly used term indicating older persons at increased risk for morbidity and mortality (1). In some ways, it is analogous in older persons with the term “failure to thrive” in young children. Unfortunately, it has been poorly defined in the medical literature. There is general agreement that frailty is not adequately defined as purely a decline in functional status, although functional status is itself a predictor of poor outcomes (2)(3)(4)(5), and Gealey (6) found that persons perceived to be frail also showed functional impairment. Brown and colleagues (7) defined frailty as a state that “occurs when there is diminished ability to carry out the important practical and social activities of daily living.” Hougaard (8) defined frailty as “a random effects model for time variables, where the random effect (frailty) has a multiplicative effect on harzard.” Rockwood and colleagues (9) suggested that the essential feature of frailty is the “notion of risk due to instability” and called for a more precise operationalization of the term. Lipsitz (10) defined frailty etiologically using a mathematical chaos theory approach suggesting that frailty occurs when the responses of an organism “lose complexity in resting dynamics and [show] maladaptive responses to perturbations.” Using the concept of synmorphosis, Bortz (11) has suggested that frailty is a result of early disease in multiple systems leading to impaired muscle strength, mobility, balance, and endurance. Recently, two groups have attempted to operationalize the definition of frailty. Fried and colleagues (12) have provided a specific list of objective, measurable criteria for frailty. Using their definition, they found frailty to be present in 6.9% of older community-dwelling persons and to be more common in women. Their definition differed from disability and comorbidity in this population and was a predictor of future functional decline and morbidity. Brown and colleagues (13) suggested that frailty could best be predicted by obstacle course performance, hip abduction strength, the semitandem portion of the Romberg test, and coordination on the pegboard test. A number of shorter tests to screen for frailty have also been developed. Vellas and colleagues (14) suggested that an abnormal one-leg standing balance was a simple and inexpensive marker of frailty. Miller and colleagues (15) found timed one-leg balance to be a predictor for frailty in inner-city elderly African-Americans. Lundin-Olsson and colleagues (16) utilized the Timed Up and Go (TAG) test done with and without carrying a glass of water. The TAG consists of rising from an armchair, walking 3 meters, turning around, and sitting down again. They found that persons who took 4.5 seconds or longer to complete the task when carrying the glass of water than when doing it without the extra task could be classified as frail. Brody and colleagues (17) produced a simple self-reported screening instrument that had a 50.7% sensitivity and a 97.8% specificity for predicting persons at risk of frailty. There is a need to compare these simpler tests to the more complex tests discussed in the previous paragraph. Frailty is the precursor of functional deterioration, which leads to recurrent hospitalization, institutionalization, and death (Fig. 1; 4–6,18–(23)). Frail persons have a decrease in social activity (12)(24)(25). This is compounded by the fact that frailty is often associated with incontinence, a major factor in decreasing social activity and leading to institutionalization (26)(27)(28). Frailty leads to a decline in mobility (29)(30) and is independently associated with osteopenia (31). This combination leads to falls associated with hip fracture and a subsequent fear of falling (32)(33)(34). Finally, frail persons appear to be at an increased risk of developing stroke (35). There are many causes of frailty, all of which can interact to prod the individual on the downward spiral of frailty. The geriatrician can make little impact upon some of these factors. These include chronological age, genes, and previous education level (12)(36)(37)(38)(39). It would appear that having apolipoprotein E4, a risk factor for both Alzheimer's disease and atherosclerosis, is a particularly good marker of future frailty (40)(41)(42)(43). Ongoing studies in centenarians comparing the highly functional versus the less functional and persons who are younger should yield, over the next decade, some extremely exciting data on the genetic components of frailty (44)(45)(46)(47)(48)(49)(50)(51)(52)(53). For simplicity's sake, based on the literature, we suggest that there are four major intrinsic factors—sarcopenia and related metabolic pathogenic factors, atherosclerosis, cognitive impairment, and malnutrition—that are responsible for the pathogenesis of frailty (Fig. 2). Frailty's severity can further be determined by a series of social factors such as low income, low education, and lack of family, church,