Assessing Frailty: Shifting the Definition to Better Recognize and Address This Common Syndrome
Frailty in older adults is often thought to be associated with brittle bones, weak muscles, or a disability that limits mobility. However, decades-long research has led to an evolution in the understanding of how frailty is defined and its underlying causes. In 2001, a group of researchers proposed a new definition of frailty that categorized it as a clinical syndrome or phenotype with definitive criteria that can be used to assess extent of frailty in an older adult. Assessing frailty is important to determine risk of experiencing adverse outcomes with aging and to prescribe effective interventions.
“Frailty is a major clinical outcome associated with aging. Gaining a better understanding of physical frailty can help older adults age more healthfully,” says Linda P. Fried, MD, MPH, dean of the Mailman School of Public Health, DeLamar Professor of public health practice, as well as epidemiology and medicine, and the director of the Robert N. Butler Columbia Aging Center. Fried specializes in geriatric medicine and is internationally renowned for her seminal work in defining frailty as a new clinical syndrome.
In 2001, Fried created a theory of the presentation on phenotype of frailty and conducted a series of studies to validate these from more than 5,300 men and women aged 65 years and older who participated in the Cardiovascular Health Study to operationalize and validate the phenotype. They assessed physical frailty by measuring five parameters that Fried theorized are related in a clinical cycle:1
• unintentional weight loss (at least 10 pounds in past year);
Frailty was defined as the presence of at least three of these measures and found in 7% to 10% of community-dwelling older adults. Frailty was found to be independently predictive of falls, worsening mobility, or disability in activities of daily living (ADL), hospitalization, and death. Their study also revealed that, although frailty was associated with higher rates of comorbid chronic conditions and disability, having a disability or chronic disease does not necessarily correspond to frailty. For example, less than 30% of older adults with disability in ADL tasks were found to be frail. This was an important finding, given that frailty was often considered synonymous with disability and comorbidity by those who work with the geriatric population.1
The definition of frailty using the above five criteria can alert geriatric professionals to at-risk older adults. Those with one or two criteria are considered prefrail; those with three or more are considered frail. “When a critical mass (≥3 of the above criteria) is present in an individual, this indicates a much-elevated risk for adverse outcomes, including falls, slowed recovery from illness, disability, dependency, and even death,” Fried emphasizes. These five criteria formed the basis for the Johns Hopkins Frailty Assessment Calculator, which can be used to diagnose frailty.
In January 2021, Fried was the lead author of a perspective2 published in Nature Aging that synthesized the published evidence on the pathophysiology underlying frailty, demonstrated that frailty is a complex clinical syndrome, and emphasized the rationale of assessing it as such using the five defining criteria in community-dwelling older adults. Her research, conducted over many years, led to the theory and supporting evidence that frailty involves a vicious cycle of symptoms and signs that causally affect each other. Once initiated, this cycle results in manifestations that are consistent with the definition of a clinical syndrome, she says.
The function and regulation of the body’s metabolic, musculoskeletal, and stress-response systems all decline normally with aging. In those with frailty, a complex negative feedback loop across multiple physiologic systems causes substantial declines, leading to dysfunction and dysregulation past a threshold of dysregulation. In their perspective article, Fried and colleagues note that research indicates that physical frailty is linked to altered energy metabolism, diminished hormonal and energy regulation, and altered musculoskeletal functioning. Research has linked the phenotype of physical frailty to aggregate abnormalities across multiple physiologic systems, assessed using common biomarkers and measures used to independently assess various health parameters, such as inflammation, anemia, hemoglobin A1c, micronutrient deficiencies, adiposity, and walking speed. Women aged 70 years and older were found to have a significantly greater odds of frailty if they had abnormalities in three or more of these parameters. Other research has shown that frail men and women aged 70 years and older showed a significantly impaired response to influenza vaccination; overall influenza rates were greater in physically frail older adults compared with nonfrail individuals.2
“The evidence that frailty is a clinical syndrome with a distinct clinical presentation, or phenotype, that marks a specific etiology or pathophysiology, is based on many years of clinical care and research to determine how to recognize the highly vulnerable subset of older adults who did not tolerate stressors well and who geriatricians labeled as frail,” Fried explains.
Advice for Geriatrics Professionals
For older adults categorized as prefrail, interventions can be initiated to slow or prevent progression to frailty. Interventions that target multiple physiologic systems at once, such as physical exercise, could potentially prevent, slow, or even reverse frailty, Fried and her colleagues report. They note that physical activity addresses all of the physiological systems involved in the frailty phenotype and can help prevent or improve frailty, with or without dietary intervention. In contrast, those targeting a single system, such as drugs for managing blood glucose or hypertension, have not been found to address the root causes of frailty. “Direct clinical intervention needs to better manage frail older adults through minimizing aggravating factors, such as polypharmacy, environmental hazards (eg, fall prevention), and discontinuities of care while optimizing health- and resilience-producing behaviors, such as physical activity,” Fried and her colleagues wrote in their perspective article.
Routinely assessing frailty and initiating effective interventions is essential as the geriatric population continues to increase. A recent global epidemiological analysis of frailty in community-dwelling adults older than age 60 years suggested that as many as 1 in 6 older adults may have frailty.3 Published evidence supports physical activity as an effective intervention to manage frailty. Physical activity is defined as any movement that uses skeletal muscles and requires energy expenditure. Exercise is defined as planned, structured, and repetitive movements, usually involving progression in intensity. For prefrail and frail adults, regular physical activity can help improve functionality and prevent or slow progression of frailty. Although the types of physical activities and exercises that most effectively increase strength, mobility, and functionality in older adults are well-established, the best methods for motivating this population to consistently be physically active have not yet been definitively proven.4
Older adults, especially those older than age 70 and with frailty, are typically inactive, and a majority do not meet recommended daily physical guidelines for a variety of reasons. Increasing daily physical activity in this population is challenging and requires that geriatrics professionals address not only physical factors, but also motivational, behavioral, and environmental factors that may be contributing to an older individual’s low physical activity levels. Research on multifactorial interventions to increase physical activity in those with frailty is ongoing and hopefully will identify the most effective program(s) for preventing or slowing frailty progression.2,4
— Jennifer Van Pelt, MA, is a freelance writer and health care researcher located in the Lancaster, Pennsylvania, area.
2. Fried LP, Cohen AA, Xue QL, Walston J, Bandeen-Roche K, Varadhan R. The physical frailty syndrome as a transition from homeostatic symphony to cacophony. Nat Aging. 2021;1(1):36-46.
4. Billot M, Calvani R, Urtamo A, et al. Preserving mobility in older adults with physical frailty and sarcopenia: opportunities, challenges, and recommendations for physical activity interventions. Clin Interv Aging. 2020;15:1675-1690.