A new prognostic strategy for adult patients with acute pulmonary embolism eligible for outpatient therapy.

We sought to derive a parsimonious predictive model to identify a subgroup of patients that will experience a low number of adverse events within 14 days of the diagnosis of pulmonary embolism. Retrospective cohort study of adult patients with acute pulmonary embolism at the Ottawa Hospital between 2007 and 2012. Primary outcome was defined as the composite of all-cause mortality, recurrent venous thromboembolism and major bleeding within 14 days. Multivariate logistic regression models were fit to model the occurrence of the primary outcome so as to guide either outpatient therapy or early discharge after initial admission. Calibration and discrimination were assessed in both the derivation and internal validation cohorts. 1143 patients were included, of whom 42% were treated as outpatients. At pulmonary embolism diagnosis, final score to predict the primary outcome included age, malignancy, intravenous drug or oxygen requirement and systolic blood pressure <90 mmHg, with an area under the curve (AUC) of 0.79 (95% CI 0.73-0.84) and 0.82 (95% CI 0.75-0.89) in the derivation and validation cohorts respectively. Conversely, final score to predict primary outcome after initial admission included age, malignancy, intravenous drug requirement and systolic blood pressure <90 mmHg (AUC: 0.70 (95% CI 0.64-0.76) and 0.72 (95% CI 0.66-0.79) in the derivation and validation cohorts). We have developed two simple clinical scores that may identify patients with pulmonary embolism at low risk of clinically meaningful outcomes during the first 14 days of follow up.