When taking care of older patients, we often have an intuitive sense of which ones will do well after an intervention and which ones won’t. This has been termed the “foot of the bed” test, or alternately something which separates a “young 80-year old” from an “old 80-year old.” Frailty is a syndrome defined as an increased physiologic vulnerability to stressors, and through its quantification we can help to standardize this clinical intuition. However, the routine measurement of frailty has largely remained outside both clinical trials and patient care.
A review published this past week (J Cardiovasc Nurs Mar/Apr 2012; 27: 120-131) calls for use of a consistent definition of frailty across studies of older adults with cardiovascular disease, in order to help determine its ability to predict outcomes. The authors support using previously defined criteria (Fried et al. J Gerontol A Biol Sci Med Sci 2001; 56: M146-M157) which consist of three or more of the following five: (1) unintentional weight loss, (2) self-reported exhaustion, (3) weakness (grip strength), (4) slow gait speed, and (5) low physical activity. In the original study by Fried et al., frailty was independently predictive of worsening disability, hospitalization, and death.
As there are a growing number of high-risk interventions that can be applied to older adults, including transcatheter aortic valve replacement (TAVR), left ventricular assist devices, and cardiac surgery, can a standardized definition of frailty help to predict which patients will derive meaningful benefit? For example, with TAVR, in the PARTNER trial (N Engl J Med 2010;363:1597-1607) where the mean age of patients was 83 years, 31% of patients undergoing TAVR still died at 1 year (despite a 20% absolute risk reduction with TAVR versus usual care). While frailty was reported, its degree of standardization (and association with outcomes) was unclear.
Can frailty help to identify a particular subgroup of older patients who may not benefit from high-risk interventions? Does it have the potential to become an important covariate in a similar manner to more traditional factors such as creatinine and ejection fraction? What are some of the barriers to its routine measurement?