Validation of a risk score identifying patients with acute pulmonary embolism, who are at low risk of clinical adverse outcome

Abstract

A clinical predictive model that accurately identifies patients with pulmonary embolism who are at low risk of adverse medical outcomes may be useful for management decisions, such as outpatient treatment. We aimed to externally validate a previously derived prognostic score identifying emergency ward patients with acute pulmonary embolism at low risk of 3-month complications. One hundred and ninety-nine consecutive patients with proven pulmonary embolism were included from the emergency centres of three teaching and general hospitals. Adverse outcomes, such as death, major bleed, or recurrent venous thromboembolism, were recorded during a 3-month follow-up. We retrospectively computed the prognostic score for each patient and determined its predictive accuracy at different threshold values. The overall 3-month risk of adverse event after the diagnosis of pulmonary embolism was 9.5%. At a threshold of 2 points, eight patients with scores at or below the cut-off (5%; 95% CI 2.6-9.6) and 11 patients with scores above this cut-off (27.5%; 95% CI 16.1-42.8) presented a complication. The negative predictive value for an adverse out-come was 95.0% (95% CI 90.4-97.4). The receiver operating characteristic curve derived from the score distribution had an area of 0.77 (95% CI 0.65-0.89). This compared favourably with the characteristics of the derivation study. We conclude that the Geneva risk score has an acceptable predictive accuracy to identify patients with pulmonary embolism at low risk for 3-month adverse outcomes. Whether this score remains accurate and useful in clinical practice should be determined in a prospective multicentre validation study.