Abstract
The term sarcopenia denotes a generalized reduction in skeletal muscle mass, quality and strength resulting in impaired physical performance. Initially recognized in the geriatric population it is attributed to age-related muscle degeneration, muscle disuse, malnutrition, chronic systemic inflammation, and anabolic states. It increases the mortality and hospitalization-rates and results in poor quality of life. The term sarcopenia was first described by Rosenberg in 1989. In 2016 it was recognized as an independent metabolic entity and was assigned a disease-specific code (ICD-10-CM). When similar presentation is seen along with obesity it is termed as “Sarcopenic Obesity.” 1
Diagnostic Criteria
The prevalence of sarcopenia and sarcopenic obesity in large population studies varied widely as different criteria were used. The Asian Working Group for Sarcopenia (AWGS-19) defined some criteria for defining sarcopenia and sarcopenic obesity; hand-grip strength <28 kg in men and <18 kg for women (muscle strength), 6-minute test <1 m/sec, short physical performance battery score <9 or five time chair stand test >12 seconds are the clinical criteria proposed by them. They also proposed a separate algorithm for community settings to pick up cases of “possible sarcopenia.” 2 The European group EWSSOP defined sarcopenia as a syndrome of progressive and generalized decline in skeletal muscle mass associated with low muscle strength or low performance. They identified two categories—acute and chronic. The latter is now accepted internationally. 3
Relation to CV Diseases, Aging and Diabetes
Sarcopenia is commonly seen in elderly patients with chronic diseases tumors and chronic cardiovascular, renal, endocrine and immunological disorders. Sarcopenia also leads to falls and fractures, cachexia and frailty. They have frequent and prolonged hospitalizations and increased mortality. Common inter-playing pathways like malnutrition decreased physical activity, insulin resistance, endothelial dysfunction and inflammation can cause sarcopenia and enhance the risk for cardiovascular diseases. It has been well-documented that sarcopenia can present as a co-morbidity in about one-third of the patients with chronic heart failure. Its pathogenesis is attributed to oxidative stress, inadequate nutrition, infiltration of skeletal muscle by fat and connective tissue and increased pro-inflammatory cytokines. Its occurrence generally denotes a rapid progression and poor outcome. 4 Oxidative stress and chronic inflammation are two main factors in the pathogenesis of atherosclerosis as well as sarcopenia.
The published studies on the relation between sarcopenia and sarcopenic obesity and type 2 diabetes and CVD are diverse and inconsistent. 5 A study by Waseer A et al., published in this issue of IJCC, has shown that among patients with T2DM, sarcopenia, obesity and sarcopenic obesity were prevalent in 55,100, 23.3%, respectively. Sarcopenia was more prevalent in T2 DM when they were associated with CVD compared to those who did not have any. They suggested that sarcopenia is a potential independent risk factor for CVD in patients with T2 DM.
Implications for Management
The main strategies for managing patients with sarcopenia and CV disease broadly include physical exercises, proper nutrition, hormone therapy and cardiac-specific therapies. Avoiding falls and fractures, resistance exercises, scientific physical rehabilitation, supervised nutritional interventions and supplementation, appropriate use of testosterone, Ghrelin or growth hormones and GDMT cardiac therapies will help in taking problems associated with sarcopenia in cardiac patients. Spironolactone is claimed to prevent skeletal muscle loss in heart failure patients. Hemodialysis patients fare better with ARBs than ACE inhibitors with respect to sarcopenia. 6
Sarcopenic Obesity
While sarcopenia is more frequent in the elderly; sarcopenic obesity is a less commonly recognized metabolic issue. It is much more prevalent in obese young sedentary adults, especially if diabetic. They are proven to have more oxidative stress, myosteatosis and mitochondrial dysfunction. The full implications of this emerging entity need further research. It is imperative to say that elderly cardiac patients, especially if they have diabetes or chronic renal disease have to be evaluated for sarcopenia which has a great bearing on the management strategies.
