Physical Frailty/Sarcopenia as a Key Predisposing Factor to Coronavirus Disease 2019 (COVID-19) and Its Complications in Older Adults

Abstract

The tremendously rising numbers of aged populations are associated with a heightened risk for motor and functional declines. Sarcopenia is an active age-related process that involves progressive losses of skeletal muscle mass, muscle strength, and muscle function. Muscle failure is a major cause of frailty, disability, falls, hospitalization, dependency, institutionalization, and low quality of life in older seniors. Therefore, sarcopenia considerably heightens the annual cost of care worldwide. This narrative review elaborates on sarcopenia as a deleterious condition in old age while spotting the light on its association with the coronavirus disease 2019 (COVID-19). It discusses its pathophysiology and the most possible options for preventing and treating sarcopenia. The literature shows that the dynamic of sarcopenia is complex, involving multifaceted physiological alterations relevant to aging, unhealthy behaviors (e.g., undernutrition or inadequate dietary intake and physical inactivity/immobility or sedentary lifestyle), and multiple pathogenic conditions such as metabolic, inflammatory, and endocrinal disorders. Frail individuals express nutritional deficiencies, immune deficit, oxidative stress, metabolic alterations, gut microbial alterations, neurological insult, etc. Such physiological dysfunctions are closely linked to increased vulnerability to COVID-19 among older adults and people with non-communicable diseases such as diabetes mellitus, cardiovascular disorders, and obesity. Available studies report higher occurrence of severe COVID-19 and COVID-19-related complications (ICU admission, mechanical ventilation, and in-hospital mortality) among frail compared with non-frail and prefrail individuals. Effective pharmacological treatments of sarcopenia are not currently available. However, physical activity and nutritional interventions (e.g., fast digestive proteins, vitamin D, and natural products such as bee products) may prevent the development of sarcopenia in early stages of the disease or limit disease progress. Such interventions may also lower vulnerability to COVID-19.