title: Clinical decision rule and D-dimer have lower clinical utility to exclude pulmonary embolism in cancer patients. Explanations and potential ameliorations.
abstract: Patients with malignancy frequently present with clinically suspected pulmonary embolism (PE). However, the safe and efficient combination of a clinical decision rule (CDR) and D-dimer test to rule out PE performs less well in patients with malignancy. We examined potential explanations and analysed whether elevating the D-dimer cut-off could improve the clinical utility. We used data on consecutive patients with suspected PE included in a multicenter management study. The performance of the Wells CDR and the D-dimer test was compared between patients with and without malignancy and multivariable analysis was used to compare the weights of the CDR variables. Furthermore, we combined the CDR (cut-off ≤4) with different D-dimer cut-off levels for the exclusion of PE. Of 3,306 patients with suspected PE, 475 (14%) had cancer. The Wells rule variables were less diagnostic in cancer patients. Increasing the D-dimer cut-off level to 700 μg/l for all ages or using an age-dependent cut-off resulted in an increase in the proportion of patients in whom PE could be excluded from 8.4% to 13% and 12%, respectively. The corresponding false-negative rates were 1.6% (95% confidence interval 0.3-8.7%) and 0.0% (0.0-6.3%). The Wells CDR and D-dimer perform less well in patients with suspected PE if they have cancer. Individual variables in the Wells rule are less diagnostic in cancer patients than in non-cancer patients with suspected PE. A CDR combined with an age-dependent D-dimer cut-off shows a modest improvement of the strategy in cancer patients.
authors.affiliation: Department of Vascular Medicine, Academic Medical Center, Amsterdam, the Netherlands. r.a.douma@amc.uva.nl
authors.forename: Renée A
authors.initials: RA
authors.lastname: Douma
authors.forename: Geerte L
authors.initials: GL
authors.lastname: van Sluis
authors.forename: Pieter W
authors.initials: PW
authors.lastname: Kamphuisen
authors.forename: Maaike
authors.initials: M
authors.lastname: Söhne
authors.forename: Frank W G
authors.initials: FW
authors.lastname: Leebeek
authors.forename: Patrick M M
authors.initials: PM
authors.lastname: Bossuyt
authors.forename: Harry R
authors.initials: HR
authors.lastname: Büller
mesh_terms: D003937:Diagnosis, Differential; D005188:False Negative Reactions; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism*; D006801:Humans; D008297:Male; D009369:Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D011237:Predictive Value of Tests; D015995:Prevalence; D011379:Prognosis; D011655:Pulmonary Embolism / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D