We compared the discriminative power of the CTOI, the RV/LV diameter ratio, and the PESI to predict mortality and VTE recurrence using Harrell’s C concordance statistic. We assessed the association of the CTOI, the RV/LV diameter ratio, and the PESI with LOS among patients admitted due to the index PE event using a shared-frailty lognormal survival model accounting for variation of LOS between study sites. LOS was censored if a patient died in hospital. Associations were adjusted for age, gender, type of PE (unprovoked versus provoked versus cancer-related), body mass index (BMI), prior VTE, central PE, concomitant deep vein thrombosis (DVT), arterial hypertension, diabetes mellitus, heart failure, chronic pulmonary disease, cerebrovascular disease, chronic liver disease, chronic renal failure, the PESI, and antiplatelet therapy/non-steroidal anti-inflammatory drugs.