In critically ill adults, greater quadriceps thickness and circumference independently predicted lower 28-day mortality risk.

A prospective cohort study involving 603 critically ill adults assessed the prognostic value of quadriceps mass and mid-upper arm circumference on 28-day mortality. Measurements included quadriceps thickness (QT-min and QT-max) and quadriceps circumference (QC) obtained via bedside ultrasonography and circumference techniques at admission. The primary outcome was mortality within 28 days of admission.

In multivariable analysis, quadriceps circumference (QC) demonstrated an independent protective association with mortality, with a hazard ratio of 0.95 per 1-cm increase (95% CI 0.91–1.00). Quadriceps thickness at minimum (QT-min) showed a stronger protective association, with a hazard ratio of 0.63 per 1-cm increase (95% CI 0.42–0.92). Similarly, quadriceps thickness at maximum (QT-max) was an independent protective factor, associated with a hazard ratio of 0.42 per 1-cm increase (95% CI 0.20–0.85).

Mid-upper arm circumference (MUAC) was not identified as an independent protective factor for mortality in this cohort. The study did not report specific adverse events, tolerability issues, or discontinuations related to the measurement procedures. No funding conflicts or specific limitations were detailed in the provided data, and the study design precludes causal conclusions regarding the relationship between muscle mass and survival outcomes.

Given the observational nature of this prospective cohort, these results should be interpreted as associations rather than evidence of causation. While the findings highlight quadriceps metrics as potential prognostic indicators in critically ill adults, further research is needed to validate these associations and explore clinical utility. Clinicians should consider these measurements as part of a broader assessment rather than standalone predictors.