Systematic Underestimation of Treatment Effects as a Result of Diagnostic Test Inaccuracy: Implications for the Interpretation and Design of Thromboprophylaxis Trials

1995 ◽  
Vol 73 (02) ◽  
pp. 167-171 ◽  
Author(s):  
Anthony Rodgers ◽  
Stephen MacMahon
Keyword(s):  
Deep Vein Thrombosis ◽  
Diagnostic Test ◽  
Diagnostic Tests ◽  
Treatment Effects ◽  
Screening Tests ◽  
Randomised Trials ◽  
Control Groups ◽  
Vein Thrombosis ◽  
And Control ◽  
Deep Vein

SummaryMany clinical trials that have assessed strategies for the prevention of deep vein thrombosis have employed diagnostic tests that are less accurate than venography. The correct interpretation of these trials has been the subject of considerable debate. This paper attempts to quantify the likely effects of the use of inaccurate diagnostic tests (in particular fibrinogen scanning) on the validity and precision of estimates of treatment effects. It is shown that, if there is no difference in the rate of misclassification of deep vein thrombosis between study and control groups, then treatment effects will tend to be systematically underestimated in trials that only use inaccurate diagnostic tests. However, for trials in which there are no false positive diagnoses, such as those employing venography, the estimate of relative treatment effects will be unbiased. This phenomenon is demonstrated empirically by data from randomised trials of antiplatelet therapy. The implications of these findings are two-fold. First, so long as the accuracy of the test is the same in study and control groups, positive trial results cannot be ascribed to diagnostic test inaccuracy. Second, unbiased estimates of relative treatment effects can be obtained by using cheap, practicable and non-invasive screening tests that are supplemented by venographic assessment of positive test results. This would facilitate the conduct of much larger randomised trials than has generally been possible when mandatory venography was used; if future trials randomised some thousands of patients and employed confirmatory venography then they would provide both unbiased and precise estimates of relative treatment effects.

scholarly journals Concomitant Use of Diosmin/Hesperidin and Oral Rivaroxaban Increases Deep Vein Recanalization and Reduces the Incidence of Post-Thrombotic Syndrome in Patients with Proximal Deep Vein Thrombosis

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 986-986
Author(s):  
Kirill Lobastov ◽  
Iliya Schastlivtsev ◽  
Victor Barinov
Keyword(s):  
Deep Vein Thrombosis ◽  
Clinical Severity ◽  
Proximal Deep Vein Thrombosis ◽  
Control Groups ◽  
Vein Thrombosis ◽  
Post Thrombotic Syndrome ◽  
And Control ◽  
Deep Vein ◽  
The Impact

Abstract Aim: To assess the impact of long-term Diosmin/Hesperidin use in the treatment of proximal deep vein thrombosis (DVT). Methods: This study was a pilot randomized open-label study with blinded outcome assessor - enrolled patients with their first episodes of popliteal-femoral DVT confirmed by duplex ultrasound (DUS). All participants were randomized into two groups: 1.) control that received a standard treatment with oral Rivaroxaban, and 2.) experimental that required additional treatment with Diosmin/Hesperidin 450/50 mg twice a day. Both drugs were used for six months. Patients were followed-up for the whole treatment period with series DUS every two months in order to evaluate the degree of recanalization by popliteal (PV), superficial femoral (SFV), and common femoral (CFV) veins' compressibility. Thrombi extension was assessed by modified Marder score. At the end of the follow-up period, patients were assessed with Villalta and venous clinical severity scores. Post-thrombotic syndrome (PTS) was diagnosed in those who had ≥5 Villalta score. Results: Sixty patients were randomized to the control and experimental groups (n=30 in each group). There were 40 men and 20 women with mean age of 56.3±13.4. Clinically unprovoked DVT was recognized in 65% of cases and left side localization in 45%. The median of Marder baseline scores were 15.0±4.8 and 11.1±4.3 in the experimental and control groups, respectively (p=0.002). After six months of treatment, the Marder score decreased to 0.8±1.6 and 2.8±3.5 in the main control groups, respectively (p=0.006). The generalized linear model repeated measures found a greater reduction in the Marder score (р <0.0001) and increased speed of recanalization on SFV (р <0.0001) with a non-significant tendency in the CFV (p=0.130) and PV (p=0.204) in the experimental group compared to the control one. Full recanalization of the PV at six months was observed in 24 patients (80%), who had received Diosmin/Hesperidin, and only in 17 persons (57%) of the control group (p=0.047). The median of Villalta score in the group treated with Diosmin/Hesperidin was significantly lower compared to the control one (2.9±2.7 versus 5.8±3.0 [p <0.0001]). The same difference was found for VCSS score (2.3±1.9 versus 4.9±1.9 [p <0001]). According to the Villalta score, PTS was recognized in six patients (20%) and 17 patients (57%) in the experimental and control groups, respectively (p=0.004). Conclusion: Long-term treatment with Diosmin/Hesperidin can increase the speed of deep vein recanalization and reduce the incidence of PTS diagnosed at six months in patients with proximal DVT treated with oral rivaroxaban. Disclosures Lobastov: Bayer: Honoraria, Speakers Bureau; Servier: Honoraria, Speakers Bureau. Schastlivtsev:Bayer: Honoraria, Speakers Bureau; Servier: Honoraria, Speakers Bureau. Barinov:Bayer: Honoraria, Speakers Bureau; Servier: Honoraria, Speakers Bureau.

scholarly journals Influence of Prescribed Blood Products on the Incidence of Deep Vein Thrombosis and Pulmonary Embolism in Surgical Patients

2017 ◽  
Vol 23 (8) ◽  
pp. 938-942
Author(s):  
Alenka Premuš Marušič ◽  
Igor Locatelli ◽  
Aleš Mrhar ◽  
Martin Caprnda ◽  
Ludovit Gaspar ◽  
...  
Keyword(s):  
Deep Vein Thrombosis ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Surgical Patients ◽  
Blood Products ◽  
Control Groups ◽  
Packed Red Blood Cells ◽  
Vein Thrombosis ◽  
And Control ◽  
Deep Vein

Deep vein thrombosis (DVT) and pulmonary embolisms (PEs) are common complications after surgical procedures. The influence of prescribed blood products on the occurrence of DVT and PE was evaluated in postsurgical patients in this retrospective case–control study. The records of 286 surgical patients were analyzed: DVT (n = 52), PE (n = 92), and a control group (n = 142). The amounts of prescribed blood, blood products, and vitamin K were reviewed, together with appropriate prescribing of low-molecular-weight heparins. The influence of prescribed blood products on the occurrence of DVT or PE was analyzed using multinomial logistic regression. We demonstrated a significant difference between the test and control groups ( P < .05) in relation to receiving packed red blood cells. Treatment with red blood cells was associated with an increased risk of PE but not DVT. Patients who developed PE after surgery were hospitalized for longer (median 10 days) than patients with DVT (median 6 days). There was no difference between the test and control groups concerning treatment with fresh frozen plasma. Inadequate thromboprophylaxis significantly increased the likelihood of DVT. There is a connection between receiving packed red blood cells and occurrence of postoperative PE in surgical patients. Thus, patients receiving red blood cells should be monitored more closely after surgery, as they are more likely to develop PE postoperatively.

SimpliRED D-dimer can reduce the diagnostic tests in suspected deep vein thrombosis

The Lancet ◽  
1998 ◽  
Vol 351 (9113) ◽  
pp. 1405-1406 ◽  
Author(s):  
Philip S Wells ◽  
David R Anderson ◽  
Janis Bormanis ◽  
Fred Guy ◽  
Michael Mitchell ◽  
...  
Keyword(s):  
Deep Vein Thrombosis ◽  
Diagnostic Tests ◽  
Vein Thrombosis ◽  
Deep Vein ◽  
D Dimer

scholarly journals Prophylactic anticoagulant therapy decreases the incidence of deep vein thrombosis in patients with solid tumors: A systematic review and meta-analysis

2017 ◽  
Vol 7 (1) ◽  
pp. 35
Author(s):  
Yunjiao Zhou ◽  
Gong Yang ◽  
Chenglei Huang
Keyword(s):  
Systematic Review ◽  
Deep Vein Thrombosis ◽  
Solid Tumors ◽  
Risk Ratio ◽  
Major Bleeding ◽  
Meta Analysis ◽  
Bleeding Events ◽  
Vein Thrombosis ◽  
And Control ◽  
Deep Vein

It is not well understood the efficacy and safety of primary deep vein thrombosis (DVT) prophylaxis of anticoagulants in patients with solid tumors. This systematic review and meta-analysis of randomized controlled trials (RCT) determines the relative ratio of primary DVT, survival rate and bleeding events among patients with solid tumors treated with anticoagulants or placebo. Comprehensive literature searches were conducted through the Pubmed, Ovid MEDLINE and EMBASE databases published from January 1st, 1993 to December 31st, 2015. Statistical analysis was performed by RevMan 5.0 software. For DVT events, therisk ratio in 16 trials between the prophylactic and control patients was statistically significant at 0.45 [0.36-0.58]; for major bleeding events, the risk ratio in 18 trials between the prophylactic and control patients was not statistically significant at 1.33 [0.99-1.79], while that in 15 trials with clinically relevant non-major bleeding was statistically significant at 1.83 [1.46-2.30]; the risk ratio for the mortality rate of patients with solid tumors in 16 trials was not statistically significant at 0.97 [0.93-1.02]. Inconclusion, the risk ratio in this meta-analysis showed a significantly reduced incidence of DVT with anticoagulant use. Treatment to patients who had solid tumors with prophylactic anticoagulants enhanced the incidence rate of non-major bleeding but has no significant impact on the incidence rate of major bleeding. No significant differences were found in the mortality outcomes between anticoagulant and non-anticoagulant groups.

Deep vein thrombosis and pulmonary emboli in neurosurgical patients: a review

1984 ◽  
Vol 61 (6) ◽  
pp. 1055-1062 ◽  
Author(s):  
Karl W. Swann ◽  
Peter McL. Black
Keyword(s):  
Deep Vein Thrombosis ◽  
Venous Thromboembolism ◽  
Anticoagulation Therapy ◽  
Screening Tests ◽  
Limb Weakness ◽  
Prophylactic Measure ◽  
Vein Thrombosis ◽  
Prophylactic Measures ◽  
Neurosurgical Patients ◽  
Deep Vein

✓ This review examines the incidence, natural history, diagnosis, prophylaxis, and management of deep vein thrombosis (DVT) and pulmonary embolism (PE) in neurosurgical patients. Recent studies estimate the incidence of postoperative DVT detected by fibrinogen scanning in neurosurgical patients to be 29% to 43%. Specific factors that enhance the risk of venous thromboembolism include previous DVT, surgery, immobilization, advanced age, obesity, limb weakness, heart failure, and lower extremity trauma. Clinical diagnosis of venous thromboembolism is unreliable but can be augmented by noninvasive screening tests such as iodine-125-fibrinogen scanning, Doppler ultrasonography, and impedance plethysmography. As prophylactic measures, mini-dose heparin and external pneumatic compression of the legs have decreased the incidence of DVT in clinical studies of neurosurgical patients. However, no prophylactic measure has been convincingly shown to prevent PE in neurosurgical patients. Thrombi involving the popliteal, deep femoral, and iliac veins appear most likely to cause significant PE. Anticoagulation therapy constitutes standard management of DVT and PE; however, in neurosurgical patients the potential for precipitating intracranial or intraspinal hemorrhage may necessitate vena caval interruption. This appears to be an effective alternative to anticoagulation.

Deep Vein Thrombosis: New Non-Invasive Diagnostic Tests

1991 ◽  
Vol 66 (01) ◽  
pp. 133-137 ◽  
Author(s):  
Harry R Büller ◽  
Anthonie WA Lensing ◽  
Jack Hirsh ◽  
Jan Wouter ten Cate
Keyword(s):  
Deep Vein Thrombosis ◽  
Diagnostic Tests ◽  
Vein Thrombosis ◽  
Non Invasive ◽  
Deep Vein
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