We have read with great interest the paper by Jurin et al. [1] reporting adverse survival in pulmonary embolism (PE) patients belonging to the first body mass index (BMI) quartile. As the authors have reported, low BMI patients were more likely to have lower hemoglobin levels, and a substantial fraction of the BMI impact on outcome was mediated by hemoglobin levels [1]. Low hemoglobin/hematocrit levels are associated with the expansion of plasma volume which accounts for the residual, non-cellular volume of the whole blood.
