Muscle mass and quality by computed tomography predicts mortality and emergency department revisits in older adults with acute pulmonary embolism.

Sarcopenia, the age-related loss of muscle mass and quality, is an indicator of frailty that can be objectively measured using computed tomography (CT) images acquired for other routine indications. CT-based muscle mass has been shown to predict adverse outcomes in many diseases, although evidence in acute pulmonary embolism (PE) is scant. A retrospective cohort study included patients ≥ 70 years diagnosed with acute PE between 2015 and 2019. Axial CT images at the carina and mid-thigh were used to measure chest muscle area (CMA), thigh muscle area (TMA), and thigh intramuscular fat area (TFMA) using semi-automated segmentation tools. Outcomes included 30-day mortality or unplanned emergency department (ED) revisit, hospital length of stay, disposition, and mortality at last follow-up. Logistic and Cox regression models were adjusted for the Pulmonary Embolism Severity Index (PESI). The cohort consisted of 205 patients (mean age 80 years; 63% females), with high-risk characteristics shown by a mean PESI score of 114. The incidence of 30-day mortality or ED revisit was 32%, 18%, and 12% in patients with low, intermediate, and high CMA, respectively (p = 0.01). CMA, TMA, and TFMA were independently and incrementally predictive of 30-day mortality or ED revisit, while CMA also predicted long-term mortality over 2 years. Patients with low muscle mass were more likely to have prolonged hospitalization and less likely to be discharged home. Muscle mass and quality can be opportunistically assessed from clinical CT scans and used to improve risk stratification and individualize decision-making in older adults with acute PE.