Explanation
Sarcopenia was defined by the European Working Group on Sarcopenia in Older People (EWGSOP) in 2010 as "a progressive and generalised loss of skeletal muscle mass and strength with a risk of adverse outcomes such as physical disability, poor quality of life (QOL) and death". In a revision of the above paper published by the EWGSOP2 in 2018, the definition of sarcopenia was updated to "a progressive and generalized skeletal muscle disorder that is associated with increased likelihood of adverse outcomes including falls, fractures, physical disability, and mortality".
Explanation
Sarcopenia can be diagnosed with the diagnostic criteria published by the Asian Working Group for Sarcopenia (AWGS). Sarcopenia is diagnosed in patients who have low muscle mass along with low muscle strength and/or low physical functioning. Low muscle mass is defined as a skeletal muscle index (the sum of muscle mass in the four limbs divided by height squared) of < 7.0 kg/m2 in men and < 5.4 kg/m2 in women in dual X-ray absorptiometry (DXA) and < 7.0 kg/m2 in men and < 5/7 kg/m2 in women in bioimpedance analysis (BIA). Another standard for low muscle mass is a calf circumference of < 34 cm in community-dwelling elderly men, < 33 cm in community-dwelling elderly women, < 30 cm in hospitalized elderly men, and < 29 cm in hospitalized elderly women. Low muscle strength is defined as a grip strength of < 26 kg in men and < 18 kg in women. Low physical performance is defined as a gait speed < 0.8 m/s.
Explanation
Sarcopenia is classified by cause as age-, activity-, nutrition-, or disease-related sarcopenia. Age-related sarcopenia, which affects roughly 10% of community-dwelling elderly people, describes an 0.5-1% decrease in muscle mass over 1 year in a person aged ≥ 40 years. Activity-related sarcopenia develops due to bedrest, a shut-in lifestyle, or "tentative rest and nil per os" in a hospital. Nutrition-related sarcopenia results from insufficient energy/protein intake or inappropriate nutrition management in the hospital. Disease-related sarcopenia includes invasion due to acute inflammation or trauma; as well as cachexia associated with cancer, chronic organ failure, or chronic inflammation.
Explanation
While treatment for sarcopenia depends on its cause, a rehabilitation nutrition perspective is helpful in all cases. For age-related sarcopenia, resistance training and intake of branched-chain amino acids is effective. For activity-related sarcopenia, getting out of bed early, early oral intake, and avoiding "tentative rest and nil per os" are important. Nutrition-related sarcopenia is treated with appropriate nutrition management; nutrition improvement involves aggressive nutrition management, such as energy accumulation. For disease-related sarcopenia, the most important thing is to treat the underlying disease; however, there is also simultaneous comprehensive treatment that involves nutrition, exercise, drugs, and mental care.
Explanation
A position paper has been written jointly by the Japanese Society of Dysphagia Rehabilitation, the Japanese Association on Sarcopenia and Frailty, the Japanese Association of Rehabilitation Nutrition, and the Society of Swallowing and Dysphagia of Japan to develop a shared understanding of sarcopenia and dysphagia; demonstrate currently available evidence related to sarcopenia and dysphagia; and make a unified proposal regarding mechanisms, diagnosis, treatment, and future prospects.
Explanation
The history of sarcopenia and dysphagia is as follows. In 1992, debate began as to whether undernutrition causes dysphagia. A paper written in 2000 suggested that dysphagia is caused by aging and undernutrition. The term "dysphagia due to sarcopenia" first appeared in 2005, while the term "sarcopenic dysphagia" first appeared in a 2012 paper by Kuroda et al. Since then, Japanese researchers have proactively conducted and reported many studies in this field, taking a global lead in it. This paper discusses whether the pathologies or phenomena of primary and secondary sarcopenia exist in swallowing muscles. Although the term "sarcopenic dysphagia" is currently used frequently, its usage has not achieved consensus.
Explanation
Sarcopenic dysphagia is defined as follows in a paper which examined a diagnostic algorithm for sarcopenic dysphagia: "Sarcopenic dysphagia is characterized by difficulty swallowing due to loss of mass and function in whole-body skeletal and swallowing muscles. Individuals without whole-body sarcopenia are not diagnosed with sarcopenic dysphagia. Neuromuscular disease-related sarcopenia is not included among the causes of sarcopenic dysphagia. Age, activity, nutrition, invasion, and cachexia-related sarcopenia are included among the causes of sarcopenia." In one study with elderly hospitalized patients without dysphagia prior to admission who were ordered not to eat for 2 days or more after admission, dysphagia was subsequently seen in 26% of patients, all of whom had whole-body sarcopenia. In contrast, no new cases of dysphagia occurred in any patients without whole-body sarcopenia.
Explanation
The diagnostic criteria for sarcopenic dysphagia seen in the table here were proposed at the 19th Annual Meeting of the Japanese Society of Dysphagia Rehabilitation. These diagnostic criteria were followed by the development of a diagnostic algorithm for sarcopenic dysphagia, which has been verified as reliable and valid.
Explanation
The diagnostic algorithm for sarcopenic dysphagia first assesses whether whole-body sarcopenia is present. The next step is to assess reduced swallowing function, followed by assessment of whether there is an obvious causative disease of sarcopenia. The final step is to assess swallowing muscle strength by measuring tongue pressure. Swallowing muscle strength is considered reduced with tongue pressure < 20 mPa. If tongue pressure is reduced, patients are considered to have "probable sarcopenic dysphagia". If tongue pressure isn't reduced or is difficult to measure, they are considered to have "possible sarcopenic dysphagia".
Explanation
The prevalence and prognosis of sarcopenic dysphagia have been examined in a prospective cohort study conducted with a group of patients hospitalized at an acute care hospital who also visited the Department of Rehabilitation Medicine for dysphagia rehabilitation. In this study, 49% of patients were diagnosed with whole-body sarcopenia based on the AWGS diagnostic criteria, while 32% of patients were diagnosed with possible or probable sarcopenic dysphagia based on the diagnostic algorithm for sarcopenic dysphagia. Swallowing function at discharge was significantly worse among patients with sarcopenic dysphagia than among patients with dysphagia due to other causes. These findings demonstrate that dysphagia rehabilitation in acute care hospitals includes many patients with whole-body sarcopenia and possible sarcopenic dysphagia, for which prognosis is poor.
Explanation
There are 3 case studies that involve treatment of sarcopenic dysphagia. The cases are characterized by old age, undernutrition, loss of independence in activities of daily living (ADL), disease (aspiration pneumonia and cancer), and severe dysphagia. Whole-body sarcopenia was evident in all 3 cases, the causes of which included aging, reduced activity, undernutrition, and disease. Along with dysphagia rehabilitation, all 3 patients underwent nutrition management with the goal of gaining weight and the energy intake per day was set at approximately 35 kcal/kg ideal body weight. Nutrition management led to a weight gain of approximately 10 kg, improvement in ADL, and improved swallowing function. As these results show, it's important for treatment for sarcopenic dysphagia to combine dysphagia rehabilitation (including swallowing muscle resistance training) and nutrition management.
Explanation
Effective methods for preventing sarcopenic dysphagia include assessment of general condition and swallowing function no more than 2 days after hospital admission, early rehabilitation, early ambulation, and early oral eating. If elderly inpatients with pneumonia begin eating orally no more than 2 days after admission, they can be discharged earlier with the capacity to eat by mouth. In aspiration pneumonia, "tentative nil per os" is prone to lead to delayed healing of pneumonia and reduced swallowing function compared with patients who begin eating orally no more than 2 days after admission. Preventing iatrogenic sarcopenia caused by "tentative rest", "tentative nil per os", and "tentative fluid and electrolyte replacement" is important for preventing sarcopenic dysphagia.
Explanation
The following issues in sarcopenic dysphagia must be addressed going forward. The basic problem is that there is no established basis for assessing dysphagia when sarcopenia develops in the swallowing muscles. Keeping the pharyngeal phase in mind, when mass and strength of the swallowing muscles are reduced, dysphagia could be clinically observed as pharyngeal residue associated with reduced strength of pharyngeal contraction and insufficient opening of the esophageal orifice. This discussion must be developed further, and a consensus must be reached. Interventional studies need to be conducted regarding sarcopenic dysphagia prevention and treatment. A particularly important question to answer is whether nutrition management aimed at improving nutrition can prevent and/or treat sarcopenic dysphagia. Dysphagia is a pathology affected by multiple factors in a complex fashion. So, factors other than nutrition management must also be taken into account. It's also important to assess swallowing muscle mass, swallowing function, and age-related changes in healthy elderly individuals.
References
- Cruz-Jentoft AJ, Baeyens JP, Bauer JM, et al.: Sarcopenia: European consensus on definition and diagnosis: Report of the European Working Group on Sarcopenia in Older People. Age Ageing, 39: 412-423, 2010.
- Cruz-Jentoft AJ, Bahat G, Bauer J, et al.: Sarcopenia: revised European consensus on definition and diagnosis. Age Ageing, 2018 doi: 10.1093/ageing/afy169.
- Chen LK, Liu LK, Woo J, et al.: Sarcopenia in Asia: consensus report of the Asian Working Group for Sarcopenia. J Am Med Dir Assoc, 15: 95-101, 2014.
- Fujishima I, Fujiu-Kurachi M, Arai H, et al.: Geriatr Gerontol Int submitted
- Kuroda Y, Kuroda R: Relationship between thinness and swallowing function in Japanese older adults: implications for sarcopenic dysphagia. J Am Geriatr Soc, 60: 1785-1786, 2012.
- Mori T, Fujishima I, Wakabayashi H, et al.: Development, reliability and validity of a diagnostic algorithm for sarcopenic dysphagia. JCSM Clinical Reports, 2: e00017, 2017.
- Maeda K, Takaki M, Akagi J: Decreased Skeletal Muscle Mass and Risk Factors of Sarcopenic Dysphagia: A Prospective Observational Cohort Study. J Gerontol A Biol Sci Med Sci, 72: 1290-1294, 2017.
- Wakabayashi H: Presbyphagia and Sarcopenic Dysphagia: Association between Aging, Sarcopenia, and Deglutition Disorders. J Frailty Aging, 3: 97-103, 2014.
- Wakabayashi H, Takahashi R, Murakami T: The prevalence and prognosis of sarcopenic dysphagia in patients who require dysphagia rehabilitation. J Nutr Health Aging, 2018 doi: 10.1007/s12603-018-1117-2.
- Maeda K, Akagi J: Treatment of Sarcopenic Dysphagia with Rehabilitation and Nutritional Support: A Comprehensive Approach. J Acad Nutr Diet, 116: 573-577, 2016.
- Wakabayashi H, Uwano R: Rehabilitation Nutrition for Possible Sarcopenic Dysphagia After Lung Cancer Surgery: A Case Report. Am J Phys Med Rehabil, 95: e84-89, 2016.
- Hashida N, Shamoto H, Maeda K, et al.: Rehabilitation and nutritional support for sarcopenic dysphagia and tongue atrophy after glossectomy: A case report. Nutrition, 35: 128-131, 2017.
- Koyama T, Maeda K, Anzai H, et al.: Early Commencement of Oral Intake and Physical Function are Associated with Early Hospital Discharge with Oral Intake in Hospitalized Elderly Individuals with Pneumonia. J Am Geriatr Soc, 63: 2183-2185, 2015.
- Maeda K, Koga T, Akagi J: Tentative nil per os leads to poor outcomes in older adults with aspiration pneumonia. Clin Nutr, 35: 1147-1152, 2016.
Recommended readings
- Japanese Association of Rehabilitation Nutrition ed:JJARN 2(1):Sarcopenia and dysphagia Update, Ishiyaku Publisher, Tokyo, 2018.
- Wakabayashi H:Feeding and Swallowing Support for the Elderly- presbyphagia, Oral Frailty, Sarcopenia, Cognitive disorder. Shinkoh-igaku,Tokyo, 2017.
- Wakabayashi H et al:The sarcopenia bible approached from the perspective of rehabilitation nutrition, Japan medical journal, Tokyo, 2018.
- Japanese Association on Sarcopenia and Frailty ,National Center for Geriatrics and Gerontology: Clinical Guidelines for Sarcopenia 2017, Life science,Tokyo, 2017.