Safely Ruling Out Deep Venous Thrombosis in Primary Care
- Harry R. Büller, MD;
- Arina J. ten Cate-Hoek, MD;
- Arno W. Hoes, MD;
- Manuela A. Joore, PhD;
- Karel G.M. Moons, PhD;
- Ruud Oudega, MD;
- Martin H. Prins, MD;
- Henri E.J.H. Stoffers, MD;
- Diane B. Toll, PhD;
- Eit F. van der Velde, MD;
- Henk C.P.M. van Weert, MD; and
- for the AMUSE (Amsterdam Maastricht Utrecht Study on thromboEmbolism) Investigators
- From the University of Amsterdam, Amsterdam; Maastricht University, Maastricht; and University Medical Center Utrecht, Utrecht, the Netherlands.
Abstract
Background: Up to 90% of patients referred for ultrasonography with suspected deep venous thrombosis (DVT) of the leg do not have the disease.
Objective: To evaluate the safety and efficiency of using a clinical decision rule that includes a point-of-care d-dimer assay at initial presentation in primary care to exclude DVT.
Design: A prospective management study.
Setting: Approximately 300 primary care practices in 3 regions of the Netherlands (Amsterdam, Maastricht, and Utrecht).
Patients: 1028 consecutive patients with clinically suspected DVT.
Intervention: Patients were managed on the basis of the result of the clinical decision rule, which included a d-dimer result. Patients with a score of 3 or less were not referred for ultrasonography and received no anticoagulant treatment; patients with a score of 4 or more were referred for ultrasonography.
Measurements: The primary outcome was symptomatic, objectively confirmed, venous thromboembolism during 3-month follow-up.
Results: The mean age of the 1028 study patients was 58 years, and 37% of patients were men. A valid score was obtained in 1002 patients (98%). In 500 patients (49%), with a score of 3 or less, 7 developed venous thromboembolism within 3 months (incidence, 1.4% [95% CI, 0.6% to 2.9%]). A total of 502 patients (49%) had a score of 4 or more; 3 did not have ultrasonography. Ultrasonography showed DVT in 125 patients (25%), for an overall prevalence in evaluable patients of 13% (125 of 1002). Of the 374 patients who had normal ultrasonography results, 4 developed venous thromboembolism within 3 months (1.1% [CI, 0.3% to 2.7%]).
Limitation: The study lacked a randomized design and relied on clinical follow-up to detect missed thrombotic disease.
Conclusion: A diagnostic management strategy in primary care by using a simple clinical decision rule and a point-of-care d-dimer assay reduces the need for referral to secondary care of patients with clinically suspected DVT by almost 50% and is associated with a low risk for subsequent venous thromboembolic events.
Funding: The Netherlands Organization for Scientific Research.
Article and Author Information
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Acknowledgment: The authors acknowledge the enthusiastic participation of general practitioners and other health care professionals who contributed to the study.
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Grant Support: By Netherlands Organization for Scientific Research grant 945-04-009.
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Potential Financial Conflicts of Interest: None disclosed.
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Reproducible Research Statement: Study protocol: Available from Dr. Prins (e-mail, mh.prins{at}epid.unimaas.nl). Statistical code: Not available. Data set: Available from Dr. Prins, subject to steering committee approval (e-mail, mh.prins{at}epid.unimaas.nl).
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Requests for Single Reprints: Martin H. Prins, MD, Department of Epidemiology, P Debyeplein 1, 6200 MD Maastricht, the Netherlands; e-mail, mh.prins{at}epid.unimaas.nl.
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Current Author Addresses: Drs. Büller, van der Velde, and van Weert: Academic Medical Center, Departments of Vascular Medicine and General Practice, University of Amsterdam, Meibergdreef 15, 1105 AZ Amsterdam, the Netherlands.
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Dr. ten Cate-Hoek: Division of Internal Medicine, Maastricht University Medical Center, P Debyelaan 25, 6202 AZ Maastricht, the Netherlands.
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Drs. Hoes, Moons, Oudega, and Toll: University Medical Center Utrecht, Julius Center for Health Sciences and Primary Care, Universiteitsweg 100, Locatie Stratenum, 3584 CG Utrecht, the Netherlands.
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Dr. Joore: Department of Clinical Epidemiology and Medical Technology Assessment, Maastricht University Medical Center, P Debyelaan 25, 6202 MD Maastricht, the Netherlands.
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Dr. Prins: Department of Clinical Epidemiology and Medical Technology Assessment, Maastricht University Medical Center, P Debyelaan 25, 6202 MD Maastricht, the Netherlands; or Division of Epidemiology, Maastricht University, P Debyeplein 1, 6200 MD Maastricht, the Netherlands.
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Dr. Stoffers: Department of General Practice and Family Medicine, Maastricht University, P Debyeplein 1, PO Box 616, 6200 MD Maastricht, the Netherlands.
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Author Contributions: Conception and design: H.R. Büller, A.J. ten Cate-Hoek, A.W. Hoes, M.A. Joore, K.G.M. Moons, R. Oudega, M.H. Prins, H.E.J.H. Stoffers, D.B. Toll, E.F. van der Velde, H.C.P.M. van der Weert.
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Analysis and interpretation of the data: H.R. Büller, A.J. ten Cate-Hoek, M.A. Joore, K.G.M. Moons, R. Oudega, M.H. Prins, H.E.J.H. Stoffers, D.B. Toll, E.F. van der Velde, H.C.P.M. van der Weert.
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Drafting of the article: H.R. Büller, A.J. ten Cate-Hoek, M.A. Joore, K.G.M. Moons, R. Oudega, M.H. Prins, H.E.J.H. Stoffers, D.B. Toll, E.F. van der Velde, H.C.P.M. van der Weert.
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Critical revision of the article for important intellectual content: H.R. Büller, A.J. ten Cate-Hoek, A.W. Hoes, M.A. Joore, K.G.M. Moons, R. Oudega, M.H. Prins, H.E.J.H. Stoffers, D.B. Toll, E.F. van der Velde, H.C.P.M. van der Weert.
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Final approval of the article: H.R. Büller, A.J. ten Cate-Hoek, A.W. Hoes, M.A. Joore, K.G.M. Moons, R. Oudega, M.H. Prins, H.E.J.H. Stoffers, D.B. Toll, E.F. van der Velde, H.C.P.M. van der Weert.
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Statistical expertise: A.W. Hoes.
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Obtaining of funding: H.R. Büller, M.A. Joore, K.G.M. Moons, R. Oudega, M.H. Prins, H.E.J.H. Stoffers, H.C.P.M. van der Weert.
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Administrative, technical, or logistic support: A.J. ten Cate-Hoek, D.B. Toll, E.F. van der Velde.
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Collection and assembly of data: A.J. ten Cate-Hoek, D.B. Toll, E.F. van der Velde.
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