Venous Thromboembolism Prophylaxis in Hospitalized Medical Patients
Authors: Amir Qaseem, Roger Chou, Linda Humphrey, Paul Shekelle
Journal: Annals of Internal Medicine (2012)

Letters20 March 2012Venous Thromboembolism Prophylaxis in Hospitalized Medical PatientsAmir Qaseem, MD, PhD, MHA, Roger Chou, MD, Linda Humphrey, MD, MPH, and Paul Shekelle, MD, PhDAmir Qaseem, MD, PhD, MHAFrom American College of Physicians, Philadelphia, PA 19106; Oregon Health and Science University, Portland, OR 97201; and West Los Angeles Veterans Affairs Medical Center, Los Angeles, CA 90073., Roger Chou, MDFrom American College of Physicians, Philadelphia, PA 19106; Oregon Health and Science University, Portland, OR 97201; and West Los Angeles Veterans Affairs Medical Center, Los Angeles, CA 90073., Linda Humphrey, MD, MPHFrom American College of Physicians, Philadelphia, PA 19106; Oregon Health and Science University, Portland, OR 97201; and West Los Angeles Veterans Affairs Medical Center, Los Angeles, CA 90073., and Paul Shekelle, MD, PhDFrom American College of Physicians, Philadelphia, PA 19106; Oregon Health and Science University, Portland, OR 97201; and West Los Angeles Veterans Affairs Medical Center, Los Angeles, CA 90073.Author, Article, and Disclosure Informationhttps://doi.org/10.7326/0003-4819-156-6-201203200-00020 SectionsAboutVisual AbstractPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinkedInRedditEmail IN RESPONSE:We thank Dr. Mills, Drs. Agutter and Malone, and Dr. Cundiff for their comments regarding the recent clinical guideline on VTE prophylaxis in hospitalized patients.In response to Dr. Mills, the pooled results from medical patients showed that prophylaxis with heparin is associated with a statistically significant reduction in PEs (absolute decrease, 4 events per 1000 persons treated) but a nonstatistically significant increase in major bleeding events (absolute increase, 1 event per 1000 persons treated) and no effect on mortality or symptomatic DVT. Hence, there is more benefit from potential reduction in PE events relative to the risk for bleeding.As far as the rating of our evidence goes, according to the GRADE system, publication bias is just one of the factors, including the number and quality of trials, consistency between trials, and precision of estimates, and others that should be considered when rating the quality of evidence and grading the strength of recommendations. Funnel plots can be helpful in understanding the risk for publication bias, but results must be interpreted cautiously because the small sample effects evaluated in funnel plots can be due to factors other than publication bias (such as differences in study quality, populations, or outcomes) (1, 2). Other approaches for examining the likelihood of publication bias have similar limitations (3). In addition, the possibility of publication bias by itself does not necessarily invalidate estimates of treatment effects. In this case, many unpublished small trials of heparin prophylaxis showing no reduced risk for PE would have to exist to lower the absolute decrease in events from 4 events per 1000 persons treated to 1 or fewer events per 1000 persons treated and result in no net benefit relative to the risk for major bleeding. This is unlikely. Therefore, we stand by our original recommendation and grading of evidence.As far as Dr. Cundiff's and Drs. Agutter and Malone's comments are concerned, our literature review only included evidence from randomized, controlled trials because they are less susceptible to bias than observational studies when designed and done correctly. Their review focused on diet and VTE and included no studies that actually evaluated the association between a prophylactic intervention and clinical outcomes. Rather, it discussed possible mechanisms for benefit and epidemiologic studies and proposed a possible dietary intervention for future research (4). Hence, this paper was not included in the review for our guideline.Amir Qaseem, MD, PhD, MHAAmerican College of PhysiciansPhiladelphia, PA 19106Roger Chou, MDLinda L. Humphrey, MD, MPHOregon Health and Science UniversityPortland, OR 97201Paul Shekelle, MD, PhDWest Los Angeles Veterans Affairs Medical CenterLos Angeles, CA 90073References1. Lau J, Ioannidis JP, Terrin N, Schmid CH, Olkin I. The case of the misleading funnel plot. BMJ. 2006;333:597-600. [PMID: 16974018] CrossrefMedlineGoogle Scholar2. Terrin N, Schmid CH, Lau J. In an empirical evaluation of the funnel plot, researchers could not visually identify publication bias. J Clin Epidemiol. 2005;58:894-901. [PMID: 16085192] CrossrefMedlineGoogle Scholar3. Guyatt GH, Oxman AD, Montori V, Vist G, Kunz R, Brozek J, et al. GRADE guidelines: 5. Rating the quality of evidence—publication bias. J Clin Epidemiol. 2011;64:1277-82. [PMID: 21802904] CrossrefMedlineGoogle Scholar4. Cundiff DK, Agutter PS, Malone PC, Pezzullo JC. Diet as prophylaxis and treatment for venous thromboembolism? Theor Biol Med Model. 2010;7:31. [PMID: 20701748] CrossrefMedlineGoogle Scholar Comments0 CommentsSign In to Submit A Comment Author, Article, and Disclosure InformationAffiliations: From American College of Physicians, Philadelphia, PA 19106; Oregon Health and Science University, Portland, OR 97201; and West Los Angeles Veterans Affairs Medical Center, Los Angeles, CA 90073.Disclosures: Any financial and nonfinancial conflicts of interest of the group members were declared, discussed, and resolved. Dr. Humphrey: Consultancy: U.S. Preventive Services Task Force. Royalties: UpToDate. Dr. Shekelle: Consultancy: ECRI Institute; Employment: Department of Veterans Affairs; Grants/grants pending (money to institution): Agency for Healthcare Research and Quality, Department of Veterans Affairs, Centers for Medicare & Medicaid Services; Royalties: UpToDate. Disclosures can also be viewed at www.acponline.org/authors/icmje/ConflictOfInterestForms.do?msNum=M11-1931. PreviousarticleNextarticle Advertisement FiguresReferencesRelatedDetailsSee AlsoVenous Thromboembolism Prophylaxis in Hospitalized Patients: A Clinical Practice Guideline From the American College of Physicians Amir Qaseem , Roger Chou , Linda L. Humphrey , Melissa Starkey , Paul Shekelle , and Venous Thromboembolism Prophylaxis in Hospitalized Medical Patients Graham Mills Venous Thromboembolism Prophylaxis in Hospitalized Medical Patients Paul S. Agutter and P. Colm Malone Venous Thromboembolism Prophylaxis in Hospitalized Medical Patients David K. Cundiff Metrics Cited ByLaparoscopic management of pedicle torsion of adnexal cysts 20 March 2012Volume 156, Issue 6Page: 474-475KeywordsConflicts of interestHemorrhageHeparinMedicareObservational studiesPopulation statisticsProphylaxisResearch quality assessmentVenous thromboembolism ePublished: 20 March 2012 Issue Published: 20 March 2012 CopyrightCopyright © 2012 by American College of Physicians. All Rights Reserved.PDF DownloadLoading ...