Low Skeletal Muscle Mass Predicts 30-day Mortality in Patients With Acute Pulmonary Embolism. A Multicenter Study

RATIONALE AND OBJECTIVES: Acute pulmonary embolism (APE) is a potentially life-threatening condition. We investigated the prognostic role of the skeletal musculature in patients with APE in a multicenter setting. MATERIALS AND METHODS: The retrospective study comprised 1996 patients, 898 (45%) female; mean age 66.2 ± 15.8 years. Skeletal muscles were measured at the T12 level. Skeletal muscle area (SMA), skeletal muscle density (SMD), and intramuscular adipose tissue (IMAT) were quantified. SMA thresholds were used for the definition of low skeletal muscle mass (LSMM): 56.1 cm² for female patients and 92.3 cm² for male patients. Myosteatosis was defined as SMD < 31.3 HU for female patients and SMD < 37.5 HU for male patients. Sex-specific median cutoffs were used for IMAT. Uni- and multivariable logistic regression models were used to assess the impact of the skeletal musculature on clinical outcomes. RESULTS: LSMM was identified in 629 patients (31.5%) and myosteatosis in 1664 (83.4%). The 30-day mortality rate was 5%. LSMM was associated with 30-day mortality, OR= 2.21, 95%-CI (1.51 - 3.22), p=0.01 (multivariable analysis). The influence of LSMM on 30-day mortality was higher in female patients (OR= 2.89, 95%-CI (1.63 - 5.14), p<0.01) than in male patients (OR= 1.80, 95%-CI (1.11 - 2.94), p=0.02). Myosteatosis and IMAT were not associated with 30-day mortality in APE. CONCLUSION: LSMM is an independent and strong predictor of 30-day mortality in APE. LSMM has a higher influence on 30-day mortality in female patients. Thus, analysis of the skeletal musculature should be included in the clinical routine in APE.