Identification of low-risk patients with acute symptomatic pulmonary embolism for outpatient therapy

Rationale: Patients with acute symptomatic pulmonary embolism (PE) deemed to be at low risk for early complications might be candidates for partial or complete outpatient treatment. Objectives: To develop and validate a clinical prediction rule that accurately identifies patients with PE and low risk of short-term complications and to compare its prognostic ability with two previously validated models (i.e., the Pulmonary Embolism Severity Index [PESI] and the Simplified PESI [sPESI]) Methods: Multivariable logistic regression of a large international cohort of patients with PE prospectively enrolled in the RIETE (Registro Informatizado de la Enfermedad TromboEmbólica) registry. Measurements and Main Results: All-cause mortality, recurrent PE, and major bleeding up to 10 days after PE diagnosis were determined. Of 18,707 eligible patients with acute symptomatic PE, 46 (0.25%) developed recurrent PE, 203 (1.09%) bled, and 471 (2.51%) died. Predictors included in the final model were chronic heart failure, recent immobilization, recent major bleeding, cancer, hypotension, tachycardia, hypoxemia, renal insufficiency, and abnormal platelet count. The area under receiver-operating characteristic curve was 0.77 (95% confidence interval [CI], 0.75-0.78) for the RIETE score, 0.72 (95% CI, 0.70-0.73) for PESI (P<0.05), and 0.71 (95% CI, 0.69-0.73) for sPESI (P<0.05). Our RIETE score outperformed the prognostic value of PESI in terms of net reclassification improvement (P<0.001), integrated discrimination improvement (P<0.001), and sPESI (net reclassification improvement, P<0.001; integrated discrimination improvement, P<0.001). Conclusions: We built a new score, based on widely available variables, that can be used to identify patients with PE at low risk of short-term complications, assisting in triage and potentially shortening duration of hospital stay.