PO-07 - Excluding pulmonary embolism in cancer patients using the Wells rule and age-adjusted D-dimer testing: an individual patient data meta-analysis

N van Es; T van der Hulle; J van Es; P L den Exter; R A Douma; R J Goekoop; I C M Mos; J G Garcia; P W Kamphuisen; M V Huisman; F A Klok; H R Büller; P M Bossuyt

doi:10.1016/S0049-3848(16)30140-2

PO-07 - Excluding pulmonary embolism in cancer patients using the Wells rule and age-adjusted D-dimer testing: an individual patient data meta-analysis

Thromb Res. 2016 Apr:140 Suppl 1:S179. doi: 10.1016/S0049-3848(16)30140-2. Epub 2016 Apr 8.

Authors

N van Es¹, T van der Hulle², J van Es¹, P L den Exter², R A Douma¹, R J Goekoop³, I C M Mos², J G Garcia⁴, P W Kamphuisen⁵, M V Huisman², F A Klok², H R Büller¹, P M Bossuyt⁶

Affiliations

¹ Dept. of Vascular Medicine, Academic Medical Center, Amsterdam, The Netherlands.
² Department of Thrombosis and Hemostasis, Leiden University Medical Center, Leiden, The Netherlands.
³ Department of Internal Medicine, HagaZiekenhuis, The Hague, The Netherlands.
⁴ Servicio de Urgencias, Hospital Universitario Príncipe de Asturias, Alcalá de Henares, Spain.
⁵ Department of Vascular Medicine, University Medical Center Groningen, Groningen, The Netherlands.
⁶ Department of Clinical Epidemiology and Biostatistics, Academic Medical Center, Amsterdam, The Netherlands.

PMID: 27161697
DOI: 10.1016/S0049-3848(16)30140-2

Abstract

Introduction: 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.

Aim: 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.

Materials and 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.