Prioritizing the Importance of Functional Capacity Assessments Among the Older Population: Report on a New AHA Statement
By 2050, the population older than 65 years of age will comprise 25% of the population, with the very old subgroup (i.e., those ≥85 years of age) comprising 4.5% of the population. Accompanying this demographic shift is a high prevalence of cardiovascular disease (CVD), comorbid diseases and geriatric syndromes.1 The majority of cardiovascular clinical trials test the response of an intervention on hard clinical outcomes; preserved function, independence and related self-efficacy may be as or more important to many older patients.2 Therefore, optimally advising older patients when deciding on treatments requires an understanding of functional capacity as a key outcome. Functional capacity defined as the individual's ability to perform survival related activities in an autonomous and independent manner. The primary metric of functional capacity is cardiorespiratory fitness (CRF).3 However, with the advances in technology, numerous functional capacity tests has been developed that are easily applied and that reflect combinations of strength, balance, mobility and frailty.
The choice of assessment tool will depend on the individual being tested, the purpose of the evaluation, or even the geographic location. Recently, Forman et al. provided practical recommendations and conceptual insights for prioritizing functional assessments in studies in a scientific statement from the American Heart Association entitled "Prioritizing Functional Capacity as a Principal End Point for Therapies Oriented to Older Adults With Cardiovascular Disease".4 Physical function is a key influence on the daily life of older adults with CVD. Although the importance of physical function is well-defined in published literature, the use of this important outcome measure for establishing the efficacy of a particular intervention among older adults should be incorporated into future clinical studies. The statement reviews types of functional assessments and their ideal use.
Types of Functional Assessments
- Aerobic Capacity: An appropriate response to an acute aerobic exercise stimulus requires robust and integrated physiological augmentation from the pulmonary, skeletal muscle and cardiovascular systems. Age, sex and genetic predispositions influence the physiological response and therefore performance during aerobic exertion. Although peak Vo2 is the gold standard for assessing CRF in younger adults; vascular, skeletal muscle, autonomic, hematologic and other physiological mechanisms are also contributory and often factor relatively more significantly in older age. Moreover, just as peak Vo2 decreases with advancing age, muscle mass and strength also decline with age.5
- Muscle Strength and Endurance: This is typically measured on a variable weight machine with a sitting chest press used for upper-body strength and knee extension used for lower-body strength. Handgrip strength is another common measure of strength that is relatively simple to perform, requiring only a hand dynamometer, and correlates well with other strength tests. Studies have shown that low muscle strength and endurance are predictive of a future decline in functional performance.6
- Balance Testing: This typically involves a combination of static and dynamic balance assessment with interval or ordinal scaling. Injuries caused by falls are a major cause of mortality among older adults.7
- Multidomain Assessments: These tools involve combinations of balance, mobility and gait speed over short distances. The short physical performance battery is a brief (10–12 minutes) three-component test combining gait speed with assessments of functional strength. Performance on each component is scored from 0 to 4 for a total score of 0 to 12. A score of ≤6 is the proposed frailty cutoff.8
- Functional Independence and Daily Activity: These are "everyday tasks," ranging from aspects of self-care that are needed daily (such as toileting and eatingoften described as basic or personal activity of daily livings) through to more complex tasks (such as shopping, using a telephoneoften described as instrumental or extended activity of daily livings).
- Frailty: Many tools are available to identify frailty among older populations. A conceptual definition of frailty is "the propensity to deteriorate in the face of a stressor." Phenotypic frailty is oriented to physical function and includes clinical features such as weakness, slowness of gait and fatigue, while cumulative deficit frailty is a summative index or proportion of deficits relative to a total number of age-related health variables considered.
- Forman DE, Rich MW, Alexander KP, et al. Cardiac care for older adults. Time for a new paradigm. J Am Coll Cardiol 2011;57:1801-10.
- Fried TR, McGraw S, Agostini JV, Tinetti ME. Views of older persons with multiple morbidities on competing outcomes and clinical decision-making. J Am Geriatr Soc 2008;56:1839-44.
- Lavie CJ, Arena R, Swift DL, et al. Exercise and the cardiovascular system: clinical science and cardiovascular outcomes. Circ Res 2015;117:207-19.
- Forman DE, Arena R, Boxer R, et al. Prioritizing functional capacity as a principal end point for therapies oriented to older adults with cardiovascular disease: a scientific statement for healthcare professionals from the American Heart Association. Circulation 2017;135:e894-918.
- Kallman DA, Plato CC, Tobin JD. The role of muscle loss in the age-related decline of grip strength: cross-sectional and longitudinal perspectives. J Gerontol 1990;45:M82-8.
- Newman AB, Kupelian V, Visser M, et al. Strength, but not muscle mass, is associated with mortality in the health, aging and body composition study cohort. J Gerontol A Biol Sci Med Sci 2006;61:72-7.
- Alamgir H, Muazzam S, Nasrullah M. Unintentional falls mortality among elderly in the United States: time for action. Injury 2012;43:2065-71.
Keywords: Geriatrics, Self Efficacy, Self Care, American Heart Association, Genetic Predisposition to Disease, Frail Elderly, Physical Exertion, Muscle Strength, Activities of Daily Living, Exercise, Outcome Assessment (Health Care), Cardiovascular System, Cardiovascular Diseases
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