Sarcopenia is more common in the elderly and causes adverse outcomes with increased morbidity and mortality. This prospective cohort study assessed the association of sarcopenia risk with the severity of COVID-19 at the time of admission and during hospitalisation and the length of hospital stay. Two hundred patients (aged ≥ 60 years) who were hospitalised for COVID-19 were enrolled using consecutive sampling between 29 December 2020 and 20 May 2021. The sarcopenia score of the patients was assessed using the Strength, Assistance in walking, Rising from a chair, Climbing stairs, and Falls questionnaire. The severity of COVID-19 was determined using the modified National Early Warning Score (m-NEWS) system for 2019 n-CoV-infected patients at admission (T1), day three (T2) and at discharge (T3). Data were analysed using SPSS, version 22 and STATA, version 14. Of the 165 patients included, thirty four (20·6 %) were at risk of sarcopenia. The length of hospital stay was slightly longer in patients with sarcopenia risk, but the difference was not significant (P = 0·600). The adjusted OR of respiratory rate (RR) > 20 /min at T1 for the sarcopenia risk group was 6·7-times higher than that for the non-sarcopenic group (P = 0·002). According to generalised estimating equations, after adjusting for confounding factors, the m-NEWS score was 5·6 units higher in patients at risk of sarcopenia (P < 0·001). Sarcopenia risk could exacerbate COVID-19 severity and increase RR at admission, as well as the need for oxygen therapy at discharge.