The effects of cause of death classification on prognostic assessment of patients with pulmonary embolism

Background: Although previous studies have provided evidence that the majority of deaths following an acute pulmonary embolism (PE) directly relate to the PE, more recent registries and cohort studies suggest otherwise. Methods: We assessed the cause of death during the first 30 days after the diagnosis of acute symptomatic PE in a consecutive series of patients. We also assessed the prognostic characteristics of the simplified Pulmonary Embolism Severity Index (sPESI) and cardiac troponin I (cTnI) obtained at the time of PE diagnosis. Results: During the first 30 days after diagnosis, 127 of the 1291 patients died (9.8%; 95% confidence interval [CI], 8.2-11.5). Sixty patients (4.6%; 95% CI, 3.5-5.8) died from definite or possible PE, and 67 (5.2%; 95% CI, 4.0-6.4) died from other causes (cancer 25, infection 18, hemorrhage 7, heart failure 7, chronic obstructive pulmonary disease 5, renal failure 1, seizures 1, unknown 3). The sPESI predicted all-cause (odds ratio [OR], 5.97; 95% CI, 1.74-20.54; P < 0.01) and PE-associated mortality (OR, 8.79; 95% CI, 1.12-68.79; P = 0.04). cTnI only predicted PE-associated mortality (adjusted OR, 2.39; 95% CI, 1.25-4.57; P < 0.01). For all-cause mortality, the sPESI low-risk strata had a negative predictive value of 98.8% (95% CI, 97.4-100) in comparison with 91.3% (95% CI, 88.9-93.6) for the cTnI. Conclusions: Within the first 30 days after the diagnosis of acute symptomatic PE, death due to PE and death due to other causes occur in a similar proportion of patients. As cTnI only predicted PE-associated mortality, low-risk sPESI had a higher negative predictive value for all-cause mortality compared with cTnI.