Prevalence and prognosis of sarcopenia in acute COVID-19 and long COVID: a systematic review and meta-analysis.

Background: A comprehensive investigation delineating the prevalence of sarcopenia across different infection phases, from acute COVID-19 to long COVID, is lacking. Meanwhile, the relationship between sarcopenia and adverse outcomes among COVID-19 patients remains inconsistent.

Materials and methods: A systematic search of MEDLINE/PubMed, Embase, Cochrane Library, Web of Science, and Scopus, before 22nd February 2025, was conducted to identify studies assessing sarcopenia prevalence in acute COVID-19 and long COVID. Random effects meta-analyses were performed to estimate the pooled prevalence of sarcopenia for acute COVID-19 and long COVID patients. Subgroup analyses stratified by assessment tool, region, income, hospitalization status, and age were performed. The associations between sarcopenia and COVID-19-related clinical outcomes were further quantified.

Results: A total of 39 studies with 6,982 individuals were included. The pooled prevalence of sarcopenia was 48.7% (95% confidence interval (CI): 39.6-57.9%) in acute COVID-19 and 23.5% (95% CI: 12.7-39.4%) in long COVID. In acute COVID-19 patients, sarcopenia was not significantly associated with length of stay (mean difference = 2.215, 95% CI: -0.004 to 4.433), mechanical ventilation (Odds ratio (OR) = 1.80, 95% CI: 0.84-3.85), admission to the intensive care unit (OR = 1.05, 95% CI: 0.63-1.77), or mortality (OR = 1.41, 95% CI: 0.86-2.32), but was significantly associated with tracheostomy (OR = 2.48, 95% CI: 1.28-4.82).

Conclusion: In conclusion, our findings indicate that sarcopenia is highly prevalent in acute COVID-19 and persists in a substantial proportion of long COVID patients, suggesting prolonged muscle loss beyond the acute phase. Future well-designed studies are needed to further investigate the association between sarcopenia and short-term and long-term prognostic outcomes in both acute and long COVID patients.