Screening for Sarcopenia (Physical Frailty) in the COVID-19 Era

Figure 1

Schematic illustration of the algorithm used for sarcopenia screening. Abbreviations: CT: computed tomography, MRI: magnetic resonance imaging, DXA: dual-energy X-ray absorptiometry, PBK: partial body potassium, BIA: bioelectrical impedance analysis, EMG: electromyography, and NMJ: neuromuscular junction. The most commonly used algorithm for the diagnosis of sarcopenia involves direct assessment of muscle strength and physical performance using gait speed and handgrip strength. When the evaluation reveals muscle weakness and poor muscle function, direct estimation of muscle mass via CT, MRI, or DXA is necessary to confirm the diagnosis. However, muscle mass can be evaluated by cheaper and less sophisticated techniques such as BIA and even by anthropometric measures when other techniques are not available. A variety of indirect measures of muscle quality can be employed in research and clinical settings in order to evaluate the effectiveness of therapeutic protocols that target sarcopenia. Pathologies underlying muscle failure as well as response of sarcopenic muscle tissues to treatment can be detected via a wide range of biomarkers. In addition, numerous health-related outcomes that affect sarcopenic people can be used as indicators of treatment effectiveness, e.g., falls and hospitalization.