title: PO-07 - Excluding pulmonary embolism in cancer patients using the Wells rule and age-adjusted D-dimer testing: an individual patient data meta-analysis.
abstract: BACKGROUND
  Among patients with clinically suspected pulmonary embolism (PE), imaging and anticoagulant treatment can be safely withheld in approximately one-third of patients based on the combination of a "PE unlikely" Wells score and a D-dimer below the age-adjusted threshold. The clinical utility of this diagnostic approach in cancer patients is less clear.
  
  
  OBJECTIVE
  To evaluate the efficiency and failure rate of the original and simplified Wells rules in combination with age-adjusted D-dimer testing in patients with active cancer.
  
  
  METHODS
  Individual patient data were used from 6 large prospective studies in which the diagnostic management of PE was guided by the original Wells rule and D-dimer testing. Study physicians classified patients as having active cancer if they had new, recurrent, or progressive cancer (excluding basal-cell or squamous-cell skin carcinoma), or cancer requiring treatment in the last 6 months. We evaluated the dichotomous Wells rule and its simplified version (Table). The efficiency of the algorithm was defined as the proportion of patients with a "PE unlikely" Wells score and a negative age-adjusted D-dimer, defined by a D-dimer below the threshold of a patient's age times 10 μg/L in patients aged ≥51 years. A diagnostic failure was defined as a patient with a "PE unlikely" Wells score and negative age-adjusted D-dimer who had symptomatic venous thromboembolism during 3 months follow-up. A one-stage random effects meta-analysis was performed to estimate the efficiency and failure.
  
  
  RESULTS
  The dataset comprised 938 patients with active cancer with a mean age of 63 years. The most frequent cancer types were breast (13%), gastrointestinal tract (11%), and lung (8%). The type of cancer was not specified in 42%. The pooled PE prevalence was 29% (95% CI 25-32). PE could be excluded in 122 patients based on a "PE unlikely" Wells score and a negative age-adjusted D-dimer (efficiency 13%; 95% CI 11-15). Two of 122 patients were diagnosed with non-fatal symptomatic venous thromboembolism during follow-up (failure rate 1.5%; 95% CI 0.13-14.8). The simplified Wells score in combination with a negative age-adjusted D-dimer had an efficiency of 3.9% (95% CI 2.0-7.6) and a failure rate of 2.4% (95% CI 0.3-15).
  
  
  CONCLUSIONS
  Among cancer patients with clinically suspected PE, imaging and anticoagulant treatment can be withheld in 1 out of every 8 patients by the original Wells rule and age-adjusted D-dimer testing. The simplified Wells rule was neither efficient nor safe in this population.
authors.affiliation: Dept. of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: N
authors.initials: N
authors.lastname: van Es
authors.affiliation: Department of Thrombosis and Hemostasis, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: T
authors.initials: T
authors.lastname: van der Hulle
authors.affiliation: Dept. of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: van Es
authors.affiliation: Department of Thrombosis and Hemostasis, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: P L
authors.initials: PL
authors.lastname: den Exter
authors.affiliation: Dept. of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: R A
authors.initials: RA
authors.lastname: Douma
authors.affiliation: Department of Internal Medicine, HagaZiekenhuis, The Hague, The Netherlands.
authors.forename: R J
authors.initials: RJ
authors.lastname: Goekoop
authors.affiliation: Department of Thrombosis and Hemostasis, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: I C M
authors.initials: IC
authors.lastname: Mos
authors.affiliation: Servicio de Urgencias, Hospital Universitario Príncipe de Asturias, Alcalá de Henares, Spain.
authors.forename: J G
authors.initials: JG
authors.lastname: Garcia
authors.affiliation: Department of Vascular Medicine, University Medical Center Groningen, Groningen, The Netherlands.
authors.forename: P W
authors.initials: PW
authors.lastname: Kamphuisen
authors.affiliation: Department of Thrombosis and Hemostasis, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: M V
authors.initials: MV
authors.lastname: Huisman
authors.affiliation: Department of Thrombosis and Hemostasis, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: F A
authors.initials: FA
authors.lastname: Klok
authors.affiliation: Dept. of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: H R
authors.initials: HR
authors.lastname: Büller
authors.affiliation: Department of Clinical Epidemiology and Biostatistics, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: P M
authors.initials: PM
authors.lastname: Bossuyt