[Coronavirus disease 2019 and frailty]

The course of coronavirus disease 2019 (COVID-19) varies from individual to individual. People of advanced age with comorbidities have been identified as having a higher risk for severe disease or to die from COVID-19. Frailty is an essential risk factor in this respect. Approximately one fifth of the middle European population are older than 65 years, and of these 10-15% can be categorized as frail. The pandemic brings the healthcare systems in many countries to their limits. Deciding which patients should be transferred to intensive care units (ICU) raises ethical discussions. In some countries the Rockwood Clinical Frailty Scale (CFS) is used to support this decision. Patients over 80 years of age suffering from COVID-19 show a 3.6-fold increase in the risk of mortality compared to the group aged 18-49 years. The risk of frail (CFS scores 6-9) patients is three times higher than for robust patients (CFS scores 1-3). A CFS score cut-off ≥ 6 clearly correlates with mortality of COVID-19 patients older than 65 years. Additionally, mid-term and long-term survival is determined by the degree of frailty at the time before COVID-19 rather than by the severity of the disease. Patients over 60 years are particularly at risk to develop a rapid loss of muscle mass during moderate or severe COVID-19. Patients being treated on ICUs lose 20-30% of their thigh extensor muscle mass within 10 days. The extent of sarcopenia associated with COVID-19 is decisive in determining the course of the disease and makes individually tailored rehabilitation programs necessary. Up to 50% of hospitalized patients need further rehabilitation after discharge. Aerobic training of low intensity combined with resistance training as well as a sufficient supply of calories and proteins in the diet are essential in this respect.