Safe exclusion of pulmonary embolism using the Wells rule and qualitative D-dimer testing in primary care: prospective cohort studyBMJ 2012; 345 doi: https://doi.org/10.1136/bmj.e6564 (Published 04 October 2012) Cite this as: BMJ 2012;345:e6564
- Geert-Jan Geersing, general practitioner1,
- Petra M G Erkens, clinical epidemiologist2,
- Wim A M Lucassen, general practitioner3,
- Harry R Büller, professor of medicine4,
- Hugo ten Cate, professor of medicine5,
- Arno W Hoes, professor of general practice1,
- Karel G M Moons, professor of clinical epidemiology1,
- Martin H Prins, professor of clinical epidemiology2,
- Ruud Oudega, general practitioner1,
- Henk C P M van Weert, professor of general practice3,
- Henri E J H Stoffers, general practitioner2
- 1Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG Utrecht, Netherlands
- 2Department of General Practice, School for Public Health and Primary Care, Maastricht University Medical Centre, Maastricht, Netherlands
- 3Department of General Practice, Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
- 4Department of Vascular Medicine, Academic Medical Center
- 5Department of Internal Medicine, Laboratory of Clinical Thrombosis and Haemostasis, Cardiovascular Research Institute Maastricht, Maastricht University Medical Centre
- Correspondence to: G J Geersing
- Accepted 13 September 2012
Objective To validate the use of the Wells clinical decision rule combined with a point of care D-dimer test to safely exclude pulmonary embolism in primary care.
Design Prospective cohort study.
Setting Primary care across three different regions of the Netherlands (Amsterdam, Maastricht, and Utrecht).
Participants 598 adults with suspected pulmonary embolism in primary care.
Interventions Doctors scored patients according to the seven variables of the Wells rule and carried out a qualitative point of care D-dimer test. All patients were referred to secondary care and diagnosed according to local protocols. Pulmonary embolism was confirmed or refuted on the basis of a composite reference standard, including spiral computed tomography and three months’ follow-up.
Main outcome measures Diagnostic accuracy (sensitivity and specificity), proportion of patients at low risk (efficiency), number of missed patients with pulmonary embolism in low risk category (false negative rate), and the presence of symptomatic venous thromboembolism, based on the composite reference standard, including events during the follow-up period of three months.
Results Pulmonary embolism was present in 73 patients (prevalence 12.2%). On the basis of a threshold Wells score of ≤4 and a negative qualitative D-dimer test result, 272 of 598 patients were classified as low risk (efficiency 45.5%). Four cases of pulmonary embolism were observed in these 272 patients (false negative rate 1.5%, 95% confidence interval 0.4% to 3.7%). The sensitivity and specificity of this combined diagnostic approach was 94.5% (86.6% to 98.5%) and 51.0% (46.7% to 55.4%), respectively.
Conclusion A Wells score of ≤4 combined with a negative qualitative D-dimer test result can safely and efficiently exclude pulmonary embolism in primary care.
We thank LFM Beenen, radiologist at the Department of Radiology of the Academic Medical Center Amsterdam, for re-evaluating all spiral computed tomography scans as part of the adjudication process.
Contributors: HRB, HCPMvW, RO, KGMM, AW, HEJHS, HtC, and MHP had the original idea for the study and were involved in writing the original study protocol. GJG, PMGE, and WAML were involved in data collection and carried out the statistical analyses. GJG, PMGE, and WAML drafted the first version of the manuscript, which was subsequently revised by the other authors. GJG, PMGE, and WAML contributed equally to the study, had full access to all of the data in the study, and take responsibility for the integrity of the data and the accuracy of the data analysis.
Funding: The Netherlands Heart Foundation funded the study (NHS-2006B237). GlaxoSmithKline and Inverness Medical co-funded the study with unrestricted research grants. All funding sources had no role in the design, conduct, analyses or reporting of the study or in the decision to submit the manuscript for publication.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: no support from any organisation for the submitted work; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; and no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: This study was approved by the medical ethics committee of the University Medical Center Utrecht, the Netherlands.
Data sharing: Additional data are available on request from the corresponding author at.
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