Guyatt GH, Eikelboom JW, Gould MK, et al. Approach to outcome measurement in the prevention of thrombosis in surgical and medical patients: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, ON, Canada.
Chest (Impact Factor: 7.48). 02/2012; 141(2 Suppl):e185S-94S. DOI: 10.1378/chest.11-2289
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This article provides the rationale for the approach to making recommendations primarily used in four articles of the Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines: orthopedic surgery, nonorthopedic surgery, nonsurgical patients, and stroke. Some of the early clinical trials of antithrombotic prophylaxis with a placebo or no treatment group used symptomatic VTE and fatal PE to measure efficacy of the treatment. These trials suggest a benefit of thromboprophylaxis in reducing fatal PE. In contrast, most of the recent clinical trials comparing the efficacy of alternative anticoagulants used a surrogate outcome, asymptomatic DVT detected at mandatory venography. This outcome is fundamentally unsatisfactory because it does not allow a trade-off with serious bleeding; that trade-off requires knowledge of the number of symptomatic events that thromboprophylaxis prevents. In this article, we review the merits and limitations of four approaches to estimating reduction in symptomatic thrombosis: (1) direct measurement of symptomatic thrombosis, (2) use of asymptomatic events for relative risks and symptomatic events from randomized controlled trials for baseline risk, (3) use of baseline risk estimates from studies that did not perform surveillance and relative effect from asymptomatic events in randomized controlled trials, and (4) use of available data to estimate the proportion of asymptomatic events that will become symptomatic. All approaches have their limitations. The optimal choice of approach depends on the nature of the evidence available.

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    • "In patients who received inadequate prophylaxis, we differentiate two groups: excessive inadequate prophylaxis, when the patient received pharmacological ATP without clinical indication, or when the administered dose was higher than recommended. On the other side, insufficient inadequate prophylaxis when the patient had an increased VTE risk but received no prescription for prophylaxis or the prescribed dose was less than recommended [9,16]. "
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    ABSTRACT: BACKGROUND: Venous thromboembolic disease (VTE) is associated with high morbi-mortality. Adherence rate to the recommendations of antithrombotic prophylaxis guidelines (ATPG) is suboptimal. The aim of this study was to describe the adequacy of antithrombotic prophylaxis (ATP) in hospitalized patients as the initial stage of a program designed to improve physician adherence to -ATP recommendations in Argentina. METHODS: This study was a multicenter, cross-sectional study that included 28 Institutions throughout 5 provinces in Argentina. RESULTS: 1315 patients were included, 729 (55.4%) were hospitalized for medical (clinical) reasons, and 586 (44.6%) for surgical reasons. Adequate ATP was provided to 66.9% of the patients and was more frequent in surgical (71%) compared to clinical (63.6%) subjects (p < 0.001). Inadequate ATP resulted from underuse in 76.6% of the patients. Among clinical, 203 (16%) had increased bleeding risk and mechanical ATP was used infrequently. CONCLUSIONS: The adequacy of ATP was better in low VTE risk clinical and surgical patients and high VTE risk in orthopedic patients. There was worse adequacy in high risk patients (with active neoplasm) and in those with pharmacological ATP contraindications, in which the use of mechanical methods was scarce. The adequacy of ATP was greater at institutions with < 150 beds compared with larger institutions. This is the first multicentric study reporting ATP in Argentina. Understanding local characteristics of medical performance within our territory is the first step in order to develop measures for improving ATP in our environment.
    Thrombosis Journal 07/2014; DOI:10.1186/1477-9560-12-15 · 1.31 Impact Factor
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    • "Ogata [19], on the other hand found that D-dimer and high NIHSS were associated with a high risk of DVT/PE in patients with intracranial hemorrhage. Much of the differences between studies may be due to small patient populations and differences in the means of assessment of DVT/PE [4]. "
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    ABSTRACT: Objective: Deep venous thrombosis (DVT) and pulmonary embolus (PE) are serious problems for patients admitted to the hospital with stroke, subarachnoid hemorrhage (SAH), intracerebral hemorrhage (ICH) and transient ischemic attack (TIA). The purpose of this paper is to further understand the factors that place certain patients at increased risk of DVT/PE. Methods: At a 600 bed hospital, a retrospective analysis of data from 2613 patients admitted with a diagnosis of stroke, SAH, ICH or TIA in the time range 1/2008 through 3/2012 was carried out. The data was taken from the hospital’s Get with the Guidelines database and included 28 variables. These included initial NIH stroke scale, length of stay, heart failure, ambulatory by day 2 after admission, altered mental status,and renal failure among others. Multiple analyses were carried out to determine whether there were univariable or multivariable effects of any of the factors on the risk for DVT/PE. Results: The risk of DVT/PE was highest in patients with SAH and ICH and smallest with TIA. Multivariable analyses were performed and revealed only altered level of consciousness or heart failure as significant risks for DVT/PE. With the limited available data, administration of subcutaneous heparin or other chemoprophylaxis did not reduce the risk of DVT/PE. Conclusion: Although many of the variables used to describe the stroke patient are correlated, in multivariable analyses only heart failure and altered level of consciousness were important risk factors for DVT/PE. The risk of DVT/PE was 7 fold greater in patients in patients with both of these risk factors.
    The Open Neurology Journal 04/2014; 8(1):1-6. DOI:10.2174/1874205X01408010001
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    • "Only 31% of studies reported data on diagnosis of deep vein thrombosis triggered by clinical suspicion and the rest reported data on DVT screening. However, estimating absolute symptomatic events from studies that included screening may be misleading [27]. If screening is positive, patients will typically receive anticoagulation. "
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    ABSTRACT: Randomized controlled trials (RCTs) that are inappropriately designed or executed may provide biased findings and mislead clinical practice. In view of recent interest in the treatment and prevention of thrombotic complications in cancer patients we evaluated the characteristics, risk of bias and their time trends in RCTs of anticoagulation in patients with cancer. We conducted a comprehensive search, including a search of four electronic databases (MEDLINE, EMBASE, ISI the Web of Science, and CENTRAL) up to February 2010. We included RCTs in which the intervention and/or comparison consisted of: vitamin K antagonists, unfractionated heparin (UFH), low molecular weight heparin (LMWH), direct thrombin inhibitors or fondaparinux. We performed descriptive analyses and assessed the association between the variables of interest and the year of publication. We included 67 RCTs with 24,071 participants. In twenty one trials (31%) DVT diagnosis was triggered by clinical suspicion; the remaining trials either screened for DVT or were unclear about their approach. 41 (61%), 22 (33%), and 11 (16%) trials respectively reported on major bleeding, minor bleeding, and thrombocytopenia. The percentages of trials satisfying risk of bias criteria were: adequate sequence generation (85%), adequate allocation concealment (61%), participants' blinding (39%), data collectors' blinding (44%), providers' blinding (41%), outcome assessors' blinding (75%), data analysts' blinding (15%), intention to treat analysis (57%), no selective outcome reporting (12%), no stopping early for benefit (97%). The mean follow-up rate was 96%. Adequate allocation concealment and the reporting of intention to treat analysis were the only two quality criteria that improved over time. Many RCTs of anticoagulation in patients with cancer appear to use insufficiently rigorous outcome assessment methods and to have deficiencies in key methodological features. It is not clear whether this reflects a problem in the design, conduct or the reporting of these trials, or both. Future trials should avoid the shortcomings described in this article.
    BMC Cancer 02/2013; 13:76. DOI:10.1186/1471-2407-13-76 · 3.36 Impact Factor
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