135 research outputs found

    The CONSORT statement: revised recommendations for improving the quality of reports of parallel group randomized trials

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    To comprehend the results of a randomized controlled trial (RCT), readers must understand its design, conduct, analysis and interpretation. That goal can only be achieved through complete transparency from authors. Despite several decades of educational efforts, the reporting of RCTs needs improvement. Investigators and editors developed the original CONSORT (Consolidated Standards of Reporting Trials) statement to help authors improve reporting by using a checklist and flow diagram. The revised CONSORT statement presented in this paper incorporates new evidence and addresses some criticisms of the original statement. The checklist items pertain to the content of the Title, Abstract, Introduction, Methods, Results and Discussion. The revised checklist includes 22-items selected because empirical evidence indicates that not reporting the information is associated with biasedestimates of treatment effect or the information is essential to judge the reliability or relevance of the findings. We intended the flow diagram to depict the passage of participants through an RCT. The revised flow diagram depicts information from four stages of a trial (enrolment, intervention allocation, follow-up, and analysis). The diagram explicitly includes the number of participants, for each intervention group, included in the primary data analysis. Inclusion of these numbers allows the reader to judge whether the authors have performed an intention-to-treat analysis. In sum, the CONSORT statement is intended to improve the reporting of an RCT, enabling readers to understand a trial's conduct and to assess the validity of its results

    Endorsement of the CONSORT Statement by High-Impact Medical Journals in China: A Survey of Instructions for Authors and Published Papers

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    The CONSORT Statement is a reporting guideline for authors when reporting randomized controlled trials (RCTs). It offers a standard way for authors to prepare RCT reports. It has been endorsed by many high-impact medical journals and by international editorial groups. This study was conducted to assess the endorsement of the CONSORT Statement by high-impact medical journals in China by reviewing their instructions for authors.A total of 200 medical journals were selected according to the Chinese Science and Technology Journal Citation Reports, 195 of which publish clinical research papers. Their instructions for authors were reviewed and all texts mentioning the CONSORT Statement or CONSORT extension papers were extracted. Any mention of the Uniform Requirements for Manuscripts Submitted to Biomedical Journals (URM) developed by the International Committee of Medical Journal Editors (ICMJE) or ‘clinical trial registration’ was also extracted. For journals endorsing the CONSORT Statement, their most recently published RCT reports were retrieved and evaluated to assess whether the journals have followed what the CONSORT Statement required. Out of the 195 medical journals publishing clinical research papers, only six (6/195, 3.08%) mentioned ‘CONSORT’ in their instructions for authors; out of the 200 medical journals surveyed, only 14 (14/200, 7.00%) mentioned ‘ICMJE’ or ‘URM’ in their instructions for authors, and another five journals stated in their instructions for authors that clinical trials should have trial registration numbers and that priority would be given to clinical trials which had been registered. Among the 62 RCT reports published in the six journals endorsing the CONSORT Statement, 20 (20/62, 32.26%) contained flow diagrams and only three (3/62, 4.84%) provided trial registration information.Medical journals in China endorsing either the CONSORT Statement or the ICMJE's URM constituted a small percentage of the total; all of these journals used ambiguous language regarding what was expected of authors

    The reporting of methods for reducing and detecting bias: an example from the WHO Misoprostol Third Stage of Labour equivalence randomised controlled trial

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    BACKGROUND: The aim of this article is to explore ways in which selection bias and ascertainment bias can be reduced and investigated in trials, by using the example of a drug trial carried out in both developed and developing countries in hospital delivery wards. METHODS: We describe an innovative and practical design for the boxes for packing the drugs as a way of increasing the security of allocation concealment and blinding. We also assess ascertainment bias using sensitivity analyses, as some unblinding could have occurred due to a potential side effect of one of the drugs. RESULTS: The sensitivity analyses indicated that the conclusions about the relative effects of the treatments could be maintained even in the unlikely worst-case scenarios. CONCLUSIONS: Detailed description of the procedures protecting against common biases and of the assessment of ascertainment bias in this trial should allow readers to confidently appraise and interpret the results obtained. In addition, our experiences will assist others in planning trials in the future

    'Allocation concealment': the evolution and adoption of a methodological term.

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    Random assignment of individual participants in clinical trials entails two steps: (i) generating an unbiased treatment allocation schedule; and (ii) applying the schedule without foreknowledge of upcoming allocations. These two steps were implicit in the famous randomized trial of streptomycin for pulmonary tuberculosis in 1948, and were recognized explicitly in some early books on controlled trials. However, half a century later, no widely accepted term denoting the process of concealing upcoming allocations had been adopted. In 1983 Thomas Chalmers and colleagues termed that process “randomization blinding,” and showed that blinded randomization and unblinded randomization were associated with differing estimates of treatment effects; however, their terminology was subsequently rarely used. In the mid-1990s we suggested that the term “allocation concealment” would be preferable to “blinded randomization,” particularly to avoid terminology that might be confused with blinding of treatments after random allocation. After controlling for more factors than had been accounted for by Chalmers and colleagues, we demonstrated an association between allocation concealment and estimates of treatment effects. Moreover, as further indication of bias, inadequately concealed trials displayed more heterogeneity than adequately concealed trials. Notably, our modeling and methodological approach to examine the associations between trial quality and estimates of treatment effects has gained recognition and achieved replication. A PubMed search for the term “allocation concealment” between 1972 and 1993 in “any field” yielded no instances, compared with 1471 between 1995 and 2016. Google Scholar found 25 matches before 1994 and over 30,000 matches after. Although the term might still be improved to avoid occasional misconceptions about its meaning, we assume that it has been widely adopted by authors and editors because they find the term useful

    Quality of reporting of randomized controlled trials in polycystic ovary syndrome

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    Background: Inadequate reporting of randomized controlled trials (RCTs) is associated with biased estimates of treatment effects. The reporting quality of RCTs involving patients with polycystic ovary syndrome (PCOS) is unknown. The purpose of this study was to assess the reporting quality of RCTs involving patients with PCOS using a standardized tool based on the Consolidated Standards of Reporting Trials (CONSORT) statement. Methods: We searched PubMed database for English-language RCTs involving patients with PCOS. Quality of reporting was assessed using a 24-item questionnaire based on the revised CONSORT checklist. Reporting was evaluated overall, and for pre- and post-CONSORT periods. RCTs on PCOS associated with fertility and non-fertility disturbances were also evaluated separately. Results: Nine of the 24 items were reported in less than 50% of the studies, while a significant improvement (P < 0.05) was detected in 12 of 24 items (50%) over the two CONSORT periods. The RCTs on PCOS with reference to fertility seem to have adhered better to CONSORT statement than RCTs not associated to fertility. Conclusion: There is empirical evidence of suboptimal reporting quality of RCTs in PCOS. Endorsement of the CONSORT statement may optimize the reporting quality and enhance the validity of research

    Recommendations by Cochrane Review Groups for assessment of the risk of bias in studies

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    <p>Abstract</p> <p>Background</p> <p>Assessing the risk of bias in individual studies in a systematic review can be done using individual components or by summarizing the study quality in an overall score.</p> <p>Methods</p> <p>We examined the instructions to authors of the 50 Cochrane Review Groups that focus on clinical interventions for recommendations on methodological quality assessment of studies.</p> <p>Results</p> <p>Forty-one of the review groups (82%) recommended quality assessment using components and nine using a scale. All groups recommending components recommended to assess concealment of allocation, compared to only two of the groups recommending scales (P < 0.0001). Thirty-five groups (70%) recommended assessment of sequence generation and 21 groups (42%) recommended assessment of intention-to-treat analysis. Only 28 groups (56%) had specific recommendations for using the quality assessment of studies analytically in reviews, with sensitivity analysis, quality as an inclusion threshold and subgroup analysis being the most commonly recommended methods. The scales recommended had problems in the individual items and some of the groups recommending components recommended items not related to bias in their quality assessment.</p> <p>Conclusion</p> <p>We found that recommendations by some groups were not based on empirical evidence and many groups had no recommendations on how to use the quality assessment in reviews. We suggest that all Cochrane Review Groups refer to the Cochrane Handbook for Systematic Reviews of Interventions, which is evidence-based, in their instructions to authors and that their own guidelines are kept to a minimum and describe only how methodological topics that are specific to their fields should be handled.</p

    Results from a blind and a non-blind randomised trial run in parallel: experience from the Estonian Postmenopausal Hormone Therapy (EPHT) Trial

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    <p>Abstract</p> <p>Background</p> <p>The Estonian Postmenopausal Hormone Therapy (EPHT) Trial assigned 4170 potential participants prior to recruitment to blind or non-blind hormone therapy (HT), with placebo or non-treatment the respective alternatives. Before having to decide on participation, women were told whether they had been randomised to the blind or non-blind trial. Eligible women who were still willing to join the trial were recruited. After recruitment participants in the non-blind trial (N = 1001) received open-label HT or no treatment, participants in the blind trial (N = 777) remained blinded until the end of the trial. The aim of this paper is to analyse the effect of blinding on internal and external validity of trial outcomes.</p> <p>Methods</p> <p>Effect of blinding was calculated as the hazard ratio of selected chronic diseases, total mortality and all outcomes. For analysing the effect of blinding on external validity, the hazard ratios from women recruited to the placebo arm and to the non-treatment arm were compared with those not recruited; for analysing the effect of blinding on internal validity, the hazard ratios from the blind trial were compared with those from the non-blind trial.</p> <p>Results</p> <p>The women recruited to the placebo arm had less cerebrovascular disease events (HR 0.43; 95% CI: 0.26-0.71) and all outcomes combined (HR 0.76; 95% CI: 0.63-0.91) than those who were not recruited. Among women recruited or not recruited to the non-treatment arm, no differences were observed for any of the outcomes studied.</p> <p>Among women recruited to the trial, the risk for coronary heart disease events (HR 0.77; 95% CI: 0.64-0.93), cerebrovascular disease events (HR 0.66; 95%CI: 0.47-0.92), and all outcomes combined (HR 0.82; 95% CI: 0.72-0.94) was smaller among participants in the blind trial than in the non-blind trial. There was no difference between the blind and the non-blind trial for total cancer (HR 0.95; 95% CI: 0.64-1.42), bone fractures (0.93; 95% CI: 0.74-1.16), and total mortality (HR 1.03; 95% CI: 0.53-1.98).</p> <p>Conclusions</p> <p>The results from blind and non-blind trials may differ, even if the target population is the same. Blinding may influence both internal and external validity. The effect of blinding may vary for different outcome events.</p> <p>Trial registration</p> <p>[<a href="http://www.controlled-trials.com/ISRCTN35338757">ISRCTN35338757</a>]</p

    Evidence at a glance: error matrix approach for overviewing available evidence

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    Contains fulltext : 88651.pdf (publisher's version ) (Open Access)BACKGROUND: Clinical evidence continues to expand and is increasingly difficult to overview. We aimed at conceptualizing a visual assessment tool, i.e., a matrix for overviewing studies and their data in order to assess the clinical evidence at a glance. METHODS: A four-step matrix was constructed using the three dimensions of systematic error, random error, and design error. Matrix step I ranks the identified studies according to the dimensions of systematic errors and random errors. Matrix step II orders the studies according to the design errors. Matrix step III assesses the three dimensions of errors in studies. Matrix step IV assesses the size and direction of the intervention effect. RESULTS: The application of this four-step matrix is illustrated with two examples: peri-operative beta-blockade initialized in relation to surgery versus placebo for major non-cardiac surgery, and antiarrhythmics for maintaining sinus rhythm after cardioversion of atrial fibrillation. When clinical evidence is deemed both internally and externally valid, the size of the intervention effect is to be assessed. CONCLUSION: The error matrix provides an overview of the validity of the available evidence at a glance, and may assist in deciding which interventions to use in clinical practice
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