Frailty syndrome


Frailty or frailty syndrome refers to a state of health in which older adults gradually lose their bodies' in-built reserves and functioning. This makes them more vulnerable, less able to recover and even apparently minor events can have drastic impacts on their physical and mental health.
Frailty can have various symptoms including muscle weakness, slower walking speed, exhaustion, unintentional weight loss, and frequent falls. Older people with certain medical conditions such as diabetes, heart disease and dementia, are also more likely to have frailty. In addition, adults living with frailty face more symptoms of anxiety and depression than those who do not.
Frailty is not an inevitable part of aging. Its development can be prevented or delayed, and its progress slowed. The most effective ways of preventing or improving frailty are regular physical activity and a healthy diet.
The prevalence of frailty varies based on countries and the assessment technique but it is estimated to range from 12% to 24% in people over 50.
Frailty can have impacts on public health due to the factors that comprise the syndrome affecting physical and mental health outcomes. There are several ways to identify, prevent, and mitigate the prevalence of frailty and the evaluation of frailty can be done through clinical assessments created to combine recognized signs and symptoms of frailty.
Malnutrition in older adults is very common and is an important contributor to frailty.

Definitions

Frailty refers to an age-related functional decline and heightened state of vulnerability. It is a worsening of functional status compared to the normal physiological process of aging. It can refer to the combination of a decline of physical and physiological aspects of a human body. The reduced reserve capacity of organ systems, muscle, and bone create a state where the body is not capable of coping with stressors such as illness or falls. Frailty can lead to increased risk of adverse side effects, complications, and mortality.
Older age by itself is not what defines frailty, it is however a syndrome found in older adults. Many adults over 65 are not living with frailty. Frailty is not one specific disease, however is a combination of many factors. Frailty does not have a specific universal criteria on which it is diagnosed; there are a combination of signs and symptoms that can lead to a diagnosis of frailty. Evaluations can be done on physical status, weight fluctuations, or subjective symptoms. Frailty most commonly refers to physical status and is not a syndrome of mental capacity such as dementia, which is a decline in cognitive function. Although, frailty can be a risk factor for the development of dementia.
Although no universal diagnostic criteria exist, some clinical screening tools are commonly used to identify frailty. These include the Fried Frailty Phenotype and a deficit accumulation frailty index. The Fried Frailty Phenotype assesses five domains commonly affected by frailty: exhaustion, weakness, slowness, physical inactivity, and weight loss. The presence of 1-2 findings is classified as "pre-frailty", 3 or more as frailty and the presence of all 5 indicates "end-stage frailty" and is associated with poor prognosis. The deficit accumulation characterization of frailty tallies deficits present in a variety of clinical areas to create a frailty index. A higher number of deficits is associated with a worse prognosis.

Signs and symptoms

Frailty is a complex condition that is a result of multiple body systems experiencing decline in function, and the more body systems that are affected, the higher the risk is for developing frailty. There is a variety of risk factors and signs that can suggest an older person having frailty. However, the development of any of these risk factors or signs alone does not establish frailty as they can be symptoms of numerous other health conditions. For establishing that a person has frailty multiple factors or signs need to be present at the same time.
Most often frailty is identified by having three out of five of the following symptoms: unintentional weight loss, muscle weakness, self-reported exhaustion, slowness and low physical activity. At the same time there are many other risk factors, signs and symptoms can be part of frailty. The presence of some factors are thought to increase the likelihood of having or developing frailty more than others. In general, risk factors, signs and symptoms can be biological, psychological, and social.

Health-related

Decreases in skeletal muscle mass and bone density are two major contributors to developing frailty in older adults. In early to middle age, bone density and muscle mass are closely related. As adults age, skeletal muscle mass or bone density may begin to decline. This decline can lead to frailty and both have been identified as contributors to disability.
Sarcopenia is the degenerative loss of skeletal muscle mass, quality, and strength associated with aging. The rate of muscle loss is dependent on exercise level, co-existing health conditions, nutrition and other factors. Sarcopenia can lead to reduction in functional status and cause significant disability from increased muscle weakness. Aging, lower levels of DHEA, testosterone, IGF-1 and increased levels of cortisol are thought to contribute to muscle wasting in those with frailty.
Osteopenia and osteoporosis are diseases of bone mineral density loss that lead to an increased risk of bone fractures, especially with falls. Frailty is associated with an increased risk of osteoporosis related bone fractures.
Frailty is also common in those with heart failure. Both frailty and heart failure share similar methods of progressive health decline and often lead to worsened health conditions when combined.
There are many other health-related factors that can be present in frailty including incontinence, lung disease, having multiple long-term health conditions, taking multiple medications regularly, malnutrition, cognitive impairment, diabetes, and obesity. Poor oral health, difficulties with chewing and swallowing, dry mouth and pain in the mouth are also signs of frailty in some people.
Conditions and symptoms related to mental health that can increase the likelihood of frailty include depression and loneliness.

Lifestyle

Lifestyle factors and behaviors that increase the likelihood of having or developing frailty include smoking, sedentary lifestyle, low level of physical exercise. Dietary factors include low intake of certain vitamins and having a higher score on the Dietary Inflammatory Index.

Demographic characteristics

People in certain demographic groups have a higher risk of frailty than others either due to direct or indirect reasons. Demographic factors include older age, being female, having lower level of education, and having low income.

Social

Certain factors in social background and situation, interpersonal relationships can also be risk factors for frailty. Such factors include living alone, being single or widowed, having lower family income or having suffered abuse.
Living in poor neighborhood conditions, in a rural area, and having low social support are also potential risk factors for frailty.

Mechanism

The causes of frailty are multifactorial involving dysregulation across many physiological systems. Frailty may be related to a proinflammatory state. A common interleukin elevated in this state is IL-6. A pro-inflammatory cytokine, IL-6 was found to be common in older adults with frailty. IL-6 is typically up-regulated by inflammatory mediators, such as C-reactive protein, released in the presence of chronic disease. Increased levels of inflammatory mediators are often associated with chronic disease; however, they may also be elevated even in the absence of chronic disease.
Sarcopenia, anemia, anabolic hormone deficiencies, and excess exposure to catabolic hormones such as cortisol have been associated with an increased likelihood of frailty. Other mechanisms associated with frailty include insulin resistance, increased glucose levels, compromised immune function, micronutrient deficiencies, and oxidative stress.
Mitochondrial dysfunction, including mitochondrial DNA mutations, cellular respiration dysfunction, and changes in mitochondrial hemostasis is thought to contribute to reduced cellular energy, production of reactive oxygen species and inflammation. This mitochondrial dysfunction is thought to contribute to the signs of frailty.
Researchers found that individual abnormal body functions may not be the best predictor of risk of frailty. However, they did conclude that once the number of conditions reaches a certain threshold, the risk of frailty increases. This finding suggests that treatment of frailty syndrome should not be focused on a single condition, but a multitude in order to increase the likelihood of better treatment results.

Theoretical understanding

Declines in physiologic reserves and resilience contribute to frailty. The risk of frailty increases with age and with the incidence of diseases. The development of frailty is also thought to involve declines in energy production, energy utilization and repair systems in the body, resulting in declines in the function of many different physiological systems. This decline in multiple systems affects the normal complex adaptive behavior that is essential to health and eventually results in frailty.
A comparison of peripheral blood mononuclear cells from frail older individuals to cells from healthy younger individuals showed evidence in the frail older individuals of increased oxidative stress, increased apurinic/pyrimidinic sites in DNA, increased accumulation of endogenous DNA damage and reduced ability to repair DNA double-strand breaks.

Diagnosis

The syndrome of geriatric frailty is hypothesized to reflect impairments in the regulation of multiple physiologic systems, embodying a lack of resilience to physiologic challenges and thus elevated risk for a range of deleterious endpoints. Generally speaking, the empirical assessment of geriatric frailty in individuals seeks ultimately to capture this or related features, though distinct approaches to such assessment have been developed in the literature.
Two most widely used approaches, different in their nature and scopes, are the physical frailty phenotype and frailty index/deficit accumulation model.