Article type
Year
Abstract
Background: Biased randomized controlled trials (RCTs) mislead clinical practice and adversely affect patients' outcomes. A number of methodological features can limit bias in RCTs. Objectives: To systematically assess the descriptive characteristics, the methodological quality and their time trends in RCTs included in six systematic reviews of anticoagulation in cancer patients.
Methods: We con- ducted a comprehensive search, including several electronic databases (MEDLINE, EMBASE, ISI the Web of Science, and CENTRAL) until February 2010. We included RCTs in which the intervention and/or comparison consisted of: vitaminK antagonists, unfractionated heparin (UFH), low molecular weight heparin (LMWH), ximelagatran or fondaparinux. We used a standardized form to abstract study descriptive characteristics and rate methodological quality (blinding of patients, providers, outcome assessors and data analysts; intention to treat analysis; early stopping for benefit; and percentage follow-up). We performed descriptive analyses and assessed the association between the variables of interest and the year of publication categorized in 5-year intervals using chi-square test.
Results: The title and abstract screening of 3986 citations identified 69 potentially eligible RCTs, of which 2 were additional reports of RCTs and were excluded. 67 unique RCTs are represented in the sample, including 24071 participants. Adequate allocation concealment was 67%, patients' blinding 40%, data collector’s blinding 40%, providers' blinding 43%, outcome assessors' blinding 71%, data analysts' blinding 16%, intention to treat analysis 64%, and stopping early for benefit 3%. The mean follow-up rate was 96%. Results of association between the variables of interest and the year of publication will be presented at the Colloquium. \HI{Conclusions: }RCTs of anticoagulation in cancer patients appear to use less rigorous outcome assessment methods and to have deficiencies in key methodological features. It is not clear whether this reflects a problem in the conduct or the reporting of these trials, or both. Trialists of anticoagulation in patients with cancer should design more rigorous trials and transparently report their methods and findings.
Methods: We con- ducted a comprehensive search, including several electronic databases (MEDLINE, EMBASE, ISI the Web of Science, and CENTRAL) until February 2010. We included RCTs in which the intervention and/or comparison consisted of: vitaminK antagonists, unfractionated heparin (UFH), low molecular weight heparin (LMWH), ximelagatran or fondaparinux. We used a standardized form to abstract study descriptive characteristics and rate methodological quality (blinding of patients, providers, outcome assessors and data analysts; intention to treat analysis; early stopping for benefit; and percentage follow-up). We performed descriptive analyses and assessed the association between the variables of interest and the year of publication categorized in 5-year intervals using chi-square test.
Results: The title and abstract screening of 3986 citations identified 69 potentially eligible RCTs, of which 2 were additional reports of RCTs and were excluded. 67 unique RCTs are represented in the sample, including 24071 participants. Adequate allocation concealment was 67%, patients' blinding 40%, data collector’s blinding 40%, providers' blinding 43%, outcome assessors' blinding 71%, data analysts' blinding 16%, intention to treat analysis 64%, and stopping early for benefit 3%. The mean follow-up rate was 96%. Results of association between the variables of interest and the year of publication will be presented at the Colloquium. \HI{Conclusions: }RCTs of anticoagulation in cancer patients appear to use less rigorous outcome assessment methods and to have deficiencies in key methodological features. It is not clear whether this reflects a problem in the conduct or the reporting of these trials, or both. Trialists of anticoagulation in patients with cancer should design more rigorous trials and transparently report their methods and findings.