Association of muscularity status with clinical and physical function outcomes in critically ill patients with COVID-19: A systematic review and meta-analysis

Abstract

Pre–coronavirus disease 2019 (COVID-19) critical care research underscored the importance of muscularity on patient outcomes. This study investigates the association between skeletal muscle mass and quality with clinical and physical function outcomes in critically ill patients with COVID-19. We systematically searched MEDLINE, EMBASE, and CINAHL from database inception to April 24, 2024, for studies using objective methods to evaluate muscularity in critically ill adults with COVID-19, without language restrictions. Co–primary outcomes were overall mortality and muscle strength. Random-effect meta-analyses were performed in RevMan 5.4.1. We included 20 studies (N = 1818), assessing muscularity via computed tomography (twelve studies), ultrasound (seven studies), and bioelectrical impedance analysis (one study); none had low risk of bias. In analyses of high vs low muscularity, high muscle mass was significantly associated with lower overall mortality (nine studies; risk ratio = 0.74; 95% CI, 0.57–0.98; P = 0.03). When muscularity was analyzed as a continuous variable, COVID-19 survivors had higher skeletal muscle area (SMA) (13 studies; mean difference [MD] = 1.18; 95% CI, 0.03–2.33; P = 0.05) confirmed by sensitivity analysis using standardized MD (0.23, 95% CI 0.05–0.42, P = 0.01) and significantly higher muscle quality (five studies; standardized MD = 0.45; 95% CI, 0.20–0.70; P = 0.0004). Muscle strength findings were inconsistent: one study showed significant correlations between muscle strength with muscle mass parameters (r = 0.365–0.375, P < 0.001) whereas another found no association. In critically ill adults with COVID-19, high muscle mass was associated with lower mortality risk. Survivors had significantly higher SMA and muscle quality. Findings on physical function outcomes remain inconclusive (PROSPERO ID: CRD42022384155).