Simplified and original wells rules plus age-adjusted D-dimer test were useful for ruling out suspected PE

Question In patients with suspected pulmonary embolism (PE), how do the simplified and original Wells rules, combined with age-adjusted D-dimer testing, compare for ruling out PE? Methods Design:Prospective cohort study for validation of previously de-veloped clinical decision rules, each combined with D-dimer testing.Setting:Individual patient data (IPD) from 6 prospective diag-nostic management studies.Patients:7268 patients (mean age 56 y, 58% women, 89% out-patients) who had clinically suspected PE and were enrolled in 1of 6 diagnostic management studies. Patients with “PE unlikely”Wells rule scores and negative D-dimer results were managedwithout imaging or anticoagulant treatment and were followedfor symptomatic venous thromboembolism (VTE).Description of prediction guides:The original and simplifiedWells rules were based on the same criteria (clinical signs oflower-extremity deep venous thrombosis [DVT], alternative di-agnosis less likely than PE, heart rate > 100 beats/min, surgeryor immobilization in the past 4 wk, previous objectively diag-nosed PE or DVT, hemoptysis, and active cancer); criteria weregiven different weights in the original rule and 1 point each inthe simplified rule. 5 of the original studies used fixed D-dimerthresholds, and therefore age-adjusted D-dimer positivitythresholds (age × 10 μg L−1) in patients > 50 years of age werecalculated post hoc for these studies.Outcomes:PE (PE at baseline or symptomatic VTE within 3 mo).