Frailty is a state of physiological deterioration and reduced ability to respond to stressors, ultimately leading to increased risk for poor outcomes including falls, disability, hospitalization, and mortality (Fried et al., 2004; Mijnarends et al., 2018; Valenzuela et al., 2019). Aging further complicates the frailty trajectory through physiological changes that result in sarcopenia (Billot et al., 2020). Scientists have traditionally characterized sarcopenia as low skeletal muscle mass and low muscle function, including strength (Cruz-Jentoft et al., 2010), which in turn affect physical performance. When there is an impairment in physical performance, the older adult begins to have challenges performing activities of daily living (Beaudart et al., 2019). Thus, loss of muscle leads to loss of physical ability. Without intervention, age-related physical frailty almost certainly leads to poor outcomes (Billot et al., 2020; Mijnarends et al., 2018). Therefore, it is imperative that nurse practitioners (NPs), particularly those practicing in primary care, have a strong foundational understanding of frailty and maintain a high level of awareness during all medical encounters with an the older adult. In many cases, frailty may be prevented, stabilized, and even reversed. Moreover, NPs, who learn to recognize those who are frail or at risk for frailty, can intervene through nutritional, psychosocial, and physical support, potentially reducing or eliminating exacerbations of the frail condition.
Frailty care models specifically designed to support nurses across the frailty trajectory are needed yet have not been addressed in the literature. Dozens of frailty screening instruments have been developed, but there is lack of consensus on which ones are best for identifying frailty risk (Walston et al., 2018), and none address frailty care from the perspective of the nurse or NP. The authors developed the Frailty Care Model to address the need for tools that help nursing professionals identify and care for older adults who are frail or at risk for frailty (Figure 1). The purpose of this article was to introduce the Frailty Care Model and its application to practice for NPs who care for older adults.
Frailty Care Model
The Frailty Care Model is a nursing-focused theoretical model to aid in the care of the robust, prefrail, or frail older adult. It differs from models such as Fried Cycle of Frailty, which uses the Frailty Phenotype instrument (Fried et al., 2004), and Rockwood Cumulative Deficit Theory and associated instrument, the Frailty Index (Rockwood et al., 2005), which are medical and physiology-based theories. The Frailty Care Model is bio-psycho-social conceptualization designed to use multiple instruments to measure physical, nutritional, and psychosocial aspects of frailty to inform care of the older adult. For additional frailty screening tools, please see Table 1.
The Frailty Care Model illustrates a theory that states: Frailty is a fluid condition of aging that will respond to interventions and will progress in the absence of interventions. It comprises three spheres: Aging Challenges Sphere, Susceptibility Sphere, and Physical Limitations Sphere. Although the three spheres reflect a progression from robust to prefrail to severe frailty, the model demonstrates cyclic patterns when interventions are used and outcomes evaluated within each of the spheres. The three spheres are within the gray oval of aging, indicating that frailty occurs in the context of older age, which will play a role in both frailty progression and interventions to treat it.
The Frailty Care Model is designed to be used in conjunction with screening tools to facilitate early identification of at-risk individuals and subsequent implementation of primary, secondary, and tertiary interventions to alter progression of frailty. Furthermore, it is an evidence-based theoretical model that should not add to the NP's burden but rather serve as a reminder to keep frailty in mind when caring for the older adult. The Frailty Care Model operates on the following assumptions.
* The at-risk or frail individual is 65 years or older.
* Frailty can occur because of any single or combination of deficits that lead to a vulnerable state.
* Frailty can be prevented, stabilized, and sometimes reversed.
* Evidence-based methods are used to measure nutritional, psychosocial, and physical strengths and deficits.
* Comorbid conditions and disabilities do not make a person frail but may be both risk factors and outcomes of frailty.
* Social, cognitive, and environmental factors are considered when identifying frailty risk.
Prevention oriented
The Frailty Care Model emphasizes prevention. The Aging Challenges Sphere can be thought of as an opportunity for primary prevention. The older adult is not yet prefrail or frail and may in fact be robust, even in the presence of comorbidities. Therefore, some who have multiple morbidities can also have high functional ability (Angulo et al., 2020). Prevention of frailty at this sphere includes identification of physical strengths and deficits, while considering the influence of social, cognitive, and environmental factors that may increase risk of later frailty. As such, the NP's goal should be to focus on avoiding progression toward frailty.
The Susceptibility Sphere encompasses some of the physiological changes that indicate high risk for frailty. At this point, the older adult may continue to be independent in activities of daily living but is experiencing other health conditions that increase risk of frailty progression. This Sphere is consistent with prefrailty to mild frailty, and the goal of care is secondary prevention to reduce progression, stabilize, or reverse prefrailty. Depression, cognitive changes, sarcopenia, and malnutrition in the Susceptibility Sphere affect the body's defenses, resulting in a weakened state. Any one or a combination of the susceptibility factors can weaken the older adult. Secondary prevention measures should therefore involve treatment for depression, cognitive changes, sarcopenia, and malnutrition as indicated.
In the Physical Limitations Sphere, the patient is already in a cycle of low physical activity and physical activity limitations. Fried (2016) described physical activity as a vicious cycle in which decreased physical activity both predicts and exacerbates frailty, and frailty in turn leads to less physical activity. Most likely, the individual requires some assistance with one or more activities of daily living. At this stage, secondary prevention tactics can still halt or reverse functional decline associated with frailty (Abellan van Kan et al., 2008a, 2008b). The older adult at this stage is moderately frail and moving toward severe frailty.
Once the older adult is severely frail with exacerbations, tertiary prevention will be required. Examples of tertiary prevention include treating any exacerbations of the frail condition to avoid discomfort or worsening of status. Frailty exacerbations include but are not limited to gait disorders, falls, disability, comorbidities, urinary incontinence, pressure injuries, sleep disorders, delirium, and cognitive disorders and require supportive strategies on the part of the NP. A severely frail individual is often incapable of independently performing activities of daily living and may be in hospice care; however, some improvement may be possible. Application of the concepts above is described in the case of an 82-year-old woman, followed by the practical implementation of the Frailty Care Model.
Maria's case
Maria is an 82-year-old woman who was born in Mexico and moved to the United States as a young woman. Although she had lived alone for years after the death of her husband, she moved in with her daughter and son-in-law 2 years ago after breaking her left hip from a fall. Maria is far from her friends in the senior living community where she lived before breaking her hip and now spends much of her day alone the 3 days per week her daughter works. In recent weeks, Maria began to withdraw from activities. Her daughter also noticed that Maria was not eating as much as before, so she made an appointment for a complete physical with the NP.
On arrival at the clinic, the medical assistant called Maria and her daughter into the office and noted that Maria had a great deal of difficulty rising from the chair in the waiting room. She told the NP about Maria's apparent weakness. While the medical assistant obtained Maria's blood pressure, heart rate, temperature, and weight, the NP reviewed Maria's history, which included type II diabetes for which she took metformin. Maria's history also included hypertension, hyperlipidemia, and history of a left knee replacement 11 years ago. Additional prescription medications included simvastatin and lisinopril. She also took over-the-counter multivitamins and acetaminophen as needed. As Maria walked into the office, the NP greeted her with a hand shake and immediately noticed Maria's weak grip. She also noticed that Maria walked slowly while leaning heavily on her walker. The NP found that Maria was able to give much of her current health history but required her daughter's help with some of the details.
With the help of her daughter, Maria had filled out a depression inventory (Geriatric Depression Scale-15 in the waiting room [Sheikh & Yesavage, 1986]). The results indicated high risk of depression. At 5 feet and 149 lbs, her body mass index was calculated at 29.1 kg/m2, indicating Maria was overweight. However, physical examination revealed an unintentional 10 pound weight loss since her last visit 6 months prior, reflecting a loss of more than 6% body weight. Maria complained of having little energy, and her daughter reported that her mother sat in her rocking recliner much of the time. The NP identified some weakness in Maria's limbs and performed a gait assessment. Along with other questions, she determined that Maria was frail.
The NP ordered a DEXA scan due to Maria's age, postmenopausal status, and history of hip fracture. The DEXA scan, while generally ordered to assess bone density, is also a valuable tool for quantifying muscle mass (Billot et al., 2020), so the NP took advantage of this added benefit to determine the extent of Maria's sarcopenia. In addition, she ordered folate, vitamin B12, and vitamin D levels to assess nutritional status. Other laboratory results included HgbA1c, comprehensive metabolic profile, and CBC with differential. She also referred Maria to physical therapy (PT) to be evaluated and treated for frailty. Maria's daughter stated that she could transport her mother to PT and that Maria's Medicare Part B and secondary insurance would pay for the PT sessions. Recognizing that Maria could likely benefit from the Medical Nutrition Therapy preventive service available to Medicare Part B beneficiaries, the NP set up an appointment with a dietitian to ensure adequate calories and protein, while adhering to a diabetic diet. The NP ordered escitalopram 5 mg daily; however, Maria declined an appointment with a geriatric psychologist. She educated Maria and her daughter on the new medication and depression diagnosis and encouraged her to seek out ways to be socially active. A follow-up visit with the NP was scheduled for 2 weeks with a plan for an in-office cognitive examination, a "brown bag" medication review, and follow-up serum sodium laboratory test. The visit concluded with a discussion of the plan of care with both Maria and her daughter, regarding treatment for frailty.
Assessment
Experts agree that frailty needs to be detected as early as possible and that all older adults older than 70 years and those with disease-related weight loss of >=5% should be routinely assessed for frailty (Morley et al., 2013). Unfortunately, in today's fast-paced practice environment, NPs face multiple competing demands during every patient encounter, and a consideration of frailty may not be foremost in the NP's mind. Frailty assessments, however, can be easily integrated into the workflow of the medical encounter and require little additional time or resources and should not require a separate appointment to conduct the assessment. Every patient encounter provides the opportunity for the NP to apply the Frailty Care Model.
The NP who cared for Maria gathered information on frailty throughout the visit. She checked weight, watched her ambulate, and evaluated her strength with a simple handshake. Although many frailty measurement tools exist for screening patients like Maria, the Frail Scale is a clinically practical tool for determining the presence of prefrailty and frailty that includes the same physical domains the NP assessed (Abellan van Kan et al., 2008a, 2008b; Morley et al., 2012). The Frail Scale is one of the simplest screening tools, and because it is easy to use and can be repeated frequently, it can help providers identify and treat frailty early in the process (Morley et al., 2012). It includes five questions that patients self-report. The domains are physical, thus additional assessment tools may be needed to evaluate social, cognitive, and environmental factors as well as nutritional. A score of three of the five domains below indicates frailty, and a score of one to two indicates prefrailty.
* Fatigue: How much of the time during the past 4 weeks did you feel tired?
* Resistance: By yourself and not using aids, do you have any difficulty walking up 10 steps without resting?
* Ambulation: By yourself and not using aids, do you have any difficulty walking a couple of blocks (e.g., several hundred yards)?
* Illness: Did a doctor ever tell you that you have [illness]? How many?
* Loss of weight: How much do you weigh? __________ [current weight] One year ago, how much did you weigh?_________[weight 1 year ago]
The Frailty Phenotype is an objective measure of the same five frailty indicators as the Frail Scale. It requires in-office testing of grip strength and walking speed (Chen et al., 2014), which makes it a more time-consuming test than the Frail Scale. Nonetheless, researchers showed that the Frailty Phenotype was an independent predictor of poor outcomes (7-year hazard ratios ranging from 1.23 to 1.79) for those who were intermediate risk for frailty (p < .05; Fried et al., 2004).
A simple measure of gait speed is another quick and valid objective test for estimating physical ability. Unfortunately, scientists do not agree on a specific speed (time/distance) for assessing frailty. Nevertheless, gait speed can still be measured and compared from visit to visit. Maria's NP was able to do a gait assessment as part of her initial visit, but this also can be performed by a medical assistant or other ancillary staff. The Short Physical Performance Battery (SPPB), a set of tests that measure balance, gait speed, and strength, can also be used. In a recent study, SPPB scores predicted fall risk in community-dwelling older adults (Welch et al., 2021). Again, objective measures may require additional time, so referral to PT would be reasonable if the NP feels such measures are needed.
For the frail older adult, physiologic reserve has declined (Chen et al., 2014), much of which is due to inflammation (Chen et al., 2014). Testing for proinflammatory markers or biomarkers of sarcopenia and malnutrition may be considered, but it should be noted that there is no specific biomarker for frailty. Furthermore, such biomarkers may be nonspecific, and positive findings may be attributable to a variety of health conditions. For this reason, measures of physical frailty as previously discussed should be adequate to inform the care of the frail or at-risk older adult.
Sphere-specific assessment considerations
The robust older adult is fully independent, in some cases despite the presence of deficits. In the Aging Challenges Sphere, the deficits of the individual may include comorbidities, disability, and other factors that challenge the older adult's ability to remain robust. These domains are influenced by social, environmental, and cognitive factors, which should therefore be considered in the assessment. Researchers demonstrated a higher risk of frailty for those who did not participate socially and for those with lower education (Duppen et al., 2019). Cultural considerations should also be taken into account. For example, among Mexican Americans like Maria, living in a Mexican American community can help reduce the risk of frailty (Duppen et al., 2019). On the other hand, neighborhood deprivation and low socioeconomic status can increase frailty risk (Duppen et al., 2019). To identify and address environmental factors, social determinants of health (SDOH) should be part of the assessment. The SDOH include economic stability, neighborhood and physical environment, education, food, community and social context, and health care systems. In addition to the environment, the Frailty Care Model includes social and cognitive factors which may influence risk of frailty. Maria's NP recognized her risk of social isolation due to being away from her senior living community. She also made plans to assess Maria's cognitive function.
Overall, poor health can exacerbate the challenges of aging. Aging and conditions associated with aging can lead to decline in mood, cognition, physical health, and nutrition. Therefore, assessment of these domains is important for even the robust older adult. The older adult is considered to be in a Susceptibility Sphere when the assessment reveals deficits in any one or a combination of more than one of these domains. The NP can then identify the presence and severity of specific deficits so that interventions can be planned to slow progression, stabilize, or reverse the course of the prefrail to frail condition. As discussed previously, handgrip strength and gait assessment can be performed. Assessing for cognitive deficits can also be performed during the office visit (e.g., Mini-Cog [Borson et al., 2003]) and is very important given that cognitive decline can complicate and add to physical decline (Aliberti et al., 2019).
Once an individual has progressed to the Physical Limitations Sphere, assessment should focus on determining the level of limitations and identifying causes. A frailty score using the Frail Scale or other screening tool will help to inform the kind of supportive care needed. The older adult, who is in the Physical Limitations Sphere, has entered a cycle of worsening frailty. The challenge then becomes increasing physical activity for an individual who is, at the same time, losing the ability to be physically active. As with the Susceptibility Sphere, in-office testing or referral to a specialist may be required or desired for objective measures of strength and endurance. Table 2 presents additional guidance on assessment for frailty.
Application of the Frailty Care Model
Diagnosis for the purposes of this article refers to using the information obtained during the subjective and objective assessment to identify the older adult's level of frailty risk using the three spheres in the Frailty Care Mode. A diagnosis of frailty does not replace other medical diagnoses but rather assists the health care team with appropriate interventions for frailty and other comorbidities. After Maria's NP completed her assessment, she diagnosed Maria as frail. Maria was no longer facing the normal challenges of aging; she had developed depression and muscle weakness. In addition, her NP wisely chose to do further testing for cognitive decline and malnutrition. The NP also knew that Maria was not in the Challenges of Aging Sphere since she had more than one, and possibly all four, of the indicators of the Susceptibility Sphere: depression, cognitive changes, sarcopenia, and malnutrition. In fact, Maria was already facing difficulties with physical activity. She had become more sedentary, had noticeable weakness and exhaustion, and relied heavily on her walker. Maria's NP determined Maria was in the Physical Limitations Sphere and took steps to reverse or slow Maria's declining physical condition before she progressed to severe frailty with exacerbations.
Maria's NP appropriately included Maria's daughter in discussions of the plan of care. Because Maria had good family support, the NP knew how important that support would be moving forward. The planning stage also included consulting with the multidisciplinary team. The NP discussed Maria's case with PT to determine next steps that might involve their assistance. Finally, she notified the dietitian that Maria would be coming and discussed specific dietary concerns.
Frailty interventions
Interventions for frailty are not sphere-specific and should be incorporated into individualized care across all spheres, from robust to severe frailty with exacerbations. Evidence-based interventions in the Frailty Care Model include nutritional, psychosocial, and physical support. Given successful intervention, the NP can help the patient prevent, stabilize, or reverse frailty and if necessary provide resources for supportive care. Without intervention, frail older adults will experience complications related to physical limitations (Physical Limitations Sphere), including falls, pressure injuries, gait disorders, and death.
Nutrition
Malnutrition from anorexia of aging must be addressed early and often. In a 2018 study (Tsutsumimoto et al., 2018), those with anorexia of aging were more likely to be frail and disabled compared with those with a normal appetite. Referral to a dietitian is appropriate in all cases. Older adults often have poor appetites, and meeting with a dietitian can help the older adult recognize which foods are important to consume in adequate amounts. Protein and caloric support along with vitamin D supplementation have been shown to be valuable interventions for older adults at-risk for frailty (Morley et al., 2013). Maria's NP ordered blood work to determine specific nutrient deficiencies. With the help of the dietitian, the NP can make dietary recommendations and add supplementation as needed.
Psychosocial
Even robust older adults are at risk for depression and cognitive decline due to aging. Encouraging self-care, healthy diet, and exercise can go a long way in preventing or slowing emotional or cognitive decline. When the NP has determined that there are deficits in mood or cognition, psychosocial intervention is appropriate. It may be necessary to refer the patient to a geriatric psychologist or psychiatrist; a geriatric, adult gerontology, or psychiatric NP; or geriatrician skilled in mental and psychological disorders of older adults. Social isolation and depression can be particularly problematic (Freer & Wallington, 2019). Encouraging older adults to stay socially active may help reduce depression related to isolation. Loneliness, in particular, has been shown to increase risk of frailty (Gale et al., 2018). After prescribing a low-dose antidepressant, Maria's NP encouraged Maria and her daughter to look for ways to increase social engagement. Social frailty can lead to greater risk of physical frailty; therefore, social activities may alleviate loneliness and potentially reduce the consequences of frailty (Makizako et al., 2018). Because Maria was alone much of the day, her daughter began taking her to the local senior center one morning per week for socialization and activities.
Physical
Physical activity is vital for preserving muscle health and reducing sarcopenia in the older adult and has been identified as the most consistently beneficial intervention for treating frailty (Chen et al., 2014). Sedentary behavior or muscle disuse exacerbate an already inevitable age-related decline in muscle health (Valenzuela et al., 2019), increasing risk for falls and disability (Mijnarends et al., 2018). Nevertheless, even prefrail and frail older adults can recover some of their lost physical robustness by becoming more physically active (Zhang et al., 2020). For the individual who is in either the Aging Challenges or Susceptibility Spheres, a wrist-worn accelerometer may help to identify those who are not physically active and at risk for frailty. It can also determine physical ability, thus providing a foundation for exercise prescription. Referrals to PT or exercise physiologists for exercise prescription are important for those in the Aging Challenges Sphere to prevent or delay a number of age-related conditions (Tsutsumimoto et al., 2018).
One important secondary prevention measure to consider when caring for the older adult who is in the Aging Challenges or Susceptibility Spheres is the treatment and control of comorbid conditions that lead to frailty. For example, dysglycemia in the older adult with diabetes was found to increase frailty risk (Abdelhafiz & Sinclair, 2022). Furthermore, comorbid conditions often lead to sedentary behavior and loss of physical function, which ultimately contributes to sarcopenia and frailty (Tolley et al., 2021). In Maria's case, comorbidities included type II diabetes, hyperlipidemia, and hypertension. Ensuring that Maria's blood sugar, lipid levels, and blood pressure stayed in good control are three of the most important interventions her NP could do. Maria's NP also planned a "brown bag" review of medications to address potential polypharmacy known to contribute to frailty (Morley et al., 2013).
The Physical Limitations Sphere can be particularly challenging to address from a prevention standpoint. The older adult becomes less able to be physically active, which then results in further physical limitations. The more physically limited the individual becomes, the less they are able to be physically active. The cycle continues as the older adult becomes more and more frail and encounters physical, cognitive, and emotional sequelae. At this point, secondary prevention strategies may include rehabilitation to gradually increase physical ability. Efforts to slow the progress or reverse frailty may have to begin with assisted ambulation or even passive range of motion, so involving PT will likely be needed. Once the older adult has developed severe frailty, they can no longer independently perform activities of daily living and may require a higher level of care intensity and support because of frailty exacerbations.
Evaluation
Ongoing evaluation of frailty should include serial assessment of the individual's responses to interventions. Even for older adults in the Aging Challenges Sphere, serial assessment using the Frail Scale or other measure is prudent to evaluate progression. In addition, nutritional, psychosocial, and physical testing can also offer positive reinforcement for the older adult. For example, follow-up with a dietitian to give the older adult feedback on successes and challenges with dietary changes can be especially valuable for the older adult who is prefrail or frail. In all cases, frequent follow-up of frailty indicators is necessary to ensure the highest possible quality of life for the older adult.
At the initial 2-week follow-up visit, Maria performed well on the Mini-Cog and the NP did not feel further testing was indicated. Her vitamin D level was borderline low, and the NP prescribed over-the-counter vitamin D3 supplementation. Her sodium level was acceptable, and the escitalopram, which she was tolerating well, was continued with a plan to titrate slowly as symptoms warranted. The remainder of her laboratory results was unremarkable. At her 6-week follow-up visit, the NP recognized that the low-dose escitalopram, PT, and dietitian visits were having a positive effect. Maria was consuming more calories and protein and had gained 3.4 pounds since her initial visit. Maria was making efforts to spend less time sitting and was helping her daughter with simple household chores. She had not experienced any falls. After reviewing medications, she was encouraged to continue with her medications, and PT and dietitian appointments, and another visit was scheduled for 2 months. As illustrated in the Frailty Care Model, evaluation is an integral part of all stages of frailty and is a continuous process.
Conclusion
Frailty may not be the first consideration when the NP is assessing the older adult; however, early identification and intervention is imperative. The authors designed the Frailty Care Model to direct NP's attention to vital components of frailty, including its likely progression if left untreated. The model further provides a theoretical framework that the NP can include in all facets of care for the older adult, whether they are robust or frail. Guided by a framework of caring, the NP's actions can have dramatic positive implications for the older adult at risk for or suffering from frailty.
The Frailty Care Model itself will need to be evaluated and may evolve over time. It is a theoretical model, and testing will help to refine the model if necessary. Given the implications of frailty, the authors plan additional work to include outcome measurement using the Frailty Care Model.
References