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"Evidence-Based Medicine methods"
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Seeing the Truth About Double Blinding
Randomized clinical trials provide reassurances that confounding factors are balanced at baseline whereas blinding is essential to assure the balance of extraneous factors thereafter. This article provides a three-part taxonomy of pitfalls that can arise because of inadequate blinding in clinical trials. We introduce a cautionary framework for readers interpreting a blinded randomized trial for evidence-based medicine. Each pitfall is illustrated with a relevant example of a potential bias resulting from knowledge of group assignment. Several pitfalls occur during the conduct of the study including inadequate blinding of the intervention group, control group, or responsible clinicians. Additional pitfalls relate to data analysis including unsubstantiated assertions of blinding and subverted tests for blinding. Further pitfalls arise due to surrounding oversight including unblinding of research ethics boards and scientific reviewers. These caveats are sources of misunderstanding when observing the apparent connection between a clinical intervention and patient outcomes. An awareness of specific pitfalls might help advance the interpretation and application of blinded randomized clinical trials to inform evidence-based medical care.
Journal Article
Efficacy of biological disease-modifying antirheumatic drugs: a systematic literature review informing the 2013 update of the EULAR recommendations for the management of rheumatoid arthritis
Objectives To update the evidence for the efficacy of biological disease-modifying antirheumatic drugs (bDMARD) in patients with rheumatoid arthritis (RA) to inform the European League Against Rheumatism(EULAR) Task Force treatment recommendations. Methods Medline, Embase and Cochrane databases were searched for articles published between January 2009 and February 2013 on infliximab, etanercept, adalimumab, certolizumab-pegol, golimumab, anakinra, abatacept, rituximab, tocilizumab and biosimilar DMARDs (bsDMARDs) in phase 3 development. Abstracts from 2011 to 2012 American College of Rheumatology (ACR) and 2011–2013 EULAR conferences were obtained. Results Fifty-one full papers, and 57 abstracts were identified. The randomised controlled trials (RCT) confirmed the efficacy of bDMARD+conventional synthetic DMARDs (csDMARDs) versus csDMARDs alone (level 1B evidence). There was some additional evidence for the use of bDMARD monotherapy, however bDMARD and MTX combination therapy for all bDMARD classes was more efficacious (1B). Clinical and radiographic responses were high with treat-to-target strategies. Earlier improvement in signs and symptoms were seen with more intensive initial treatment strategies, but outcomes were similar upon addition of bDMARDs in patients with insufficient response to MTX. In general, radiographic progression was lower with bDMARD use, mainly due to initial treatment effects. Although patients may achieve bDMARD- and drug-free remission, maintenance of clinical responses was higher with bDMARD continuation (1B), but bDMARD dose reduction could be applied (1B). There was still no RCT data for bDMARD switching. Conclusions The systematic literature review confirms efficacy of biological DMARDs in RA. It addresses different treatment strategies with the potential for reduction in therapy, particularly with early disease control, and highlights emerging therapies.
Journal Article
Evaluation of the Cochrane Collaboration’s tool for assessing the risk of bias in randomized trials: focus groups, online survey, proposed recommendations and their implementation
Background
In 2008, the Cochrane Collaboration introduced a tool for assessing the risk of bias in clinical trials included in Cochrane reviews. The risk of bias (RoB) tool is based on narrative descriptions of evidence-based methodological features known to increase the risk of bias in trials.
Methods
To assess the usability of this tool, we conducted an evaluation by means of focus groups, online surveys and a face-to-face meeting. We obtained feedback from a range of stakeholders within The Cochrane Collaboration regarding their experiences with, and perceptions of, the RoB tool and associated guidance materials. We then assessed this feedback in a face-to-face meeting of experts and stakeholders and made recommendations for improvements and further developments of the RoB tool.
Results
The survey attracted 380 responses. Respondents reported taking an average of between 10 and 60 minutes per study to complete their RoB assessments, which 83% deemed acceptable. Most respondents (87% of authors and 95% of editorial staff) thought RoB assessments were an improvement over past approaches to trial quality assessment. Most authors liked the standardized approach (81%) and the ability to provide quotes to support judgements (74%). A third of participants disliked the increased workload and found the wording describing RoB judgements confusing. The RoB domains reported to be the most difficult to assess were incomplete outcome data and selective reporting of outcomes. Authors expressed the need for more guidance on how to incorporate RoB assessments into meta-analyses and review conclusions. Based on this evaluation, recommendations were made for improvements to the RoB tool and the associated guidance. The implementation of these recommendations is currently underway.
Conclusions
Overall, respondents identified positive experiences and perceptions of the RoB tool. Revisions of the tool and associated guidance made in response to this evaluation, and improved provision of training, may improve implementation.
Journal Article
Defining decision thresholds for judgments on health benefits and harms using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) Evidence to Decision (EtD) frameworks: a protocol for a randomised methodological study (GRADE-THRESHOLD)
IntroductionThe Grading of Recommendations Assessment, Development and Evaluation (GRADE) and similar Evidence to Decision (EtD) frameworks require its users to judge how substantial the effects of interventions are on desirable and undesirable people-important health outcomes. However, decision thresholds (DTs) that could help understand the magnitude of intervention effects and serve as reference for interpretation of findings are not yet available.The objective of this study is an approach to derive and use DTs for EtD judgments about the magnitude of health benefits and harms. We hypothesise that approximate DTs could have the ability to discriminate between the existing four categories of EtD judgments (Trivial, Small, Moderate, Large), support panels of decision-makers in their work, and promote consistency and transparency in judgments.Methods and analysisWe will conduct a methodological randomised controlled trial to collect the data that allow deriving the DTs. We will invite clinicians, epidemiologists, decision scientists, health research methodologists, experts in Health Technology Assessment (HTA), members of guideline development groups and the public to participate in the trial. Then, we will investigate the validity of our DTs by measuring the agreement between judgments that were made in the past by guideline panels and the judgments that our DTs approach would suggest if applied on the same guideline data.Ethics and disseminationThe Hamilton Integrated Research Ethics Board reviewed this study as a quality improvement study and determined that it requires no further consent. Survey participants will be required to read a consent statement in order to participate in this study at the beginning of the trial. This statement reads: You are being invited to participate in a research project which aims to identify indicative DTs that could assist users of the GRADE EtD frameworks in making judgments. Your input will be used in determining these indicative thresholds. By completing this survey, you provide consent that the anonymised data collected will be used for the research study and to be summarised in aggregate in publication and electronic tools.PROTOCOL registration numberNCT05237635.
Journal Article
Effects of evidence-based strategies to reduce the socioeconomic gradient of uptake in the English NHS Bowel Cancer Screening Programme (ASCEND): four cluster-randomised controlled trials
Uptake in the national colorectal cancer screening programme in England varies by socioeconomic status. We assessed four interventions aimed at reducing this gradient, with the intention of improving the health benefits of screening.
All people eligible for screening (men and women aged 60–74 years) across England were included in four cluster-randomised trials. Randomisation was based on day of invitation. Each trial compared the standard information with the standard information plus the following supplementary interventions: trial 1 (November, 2012), a supplementary leaflet summarising the gist of the key information; trial 2 (March, 2012), a supplementary narrative leaflet describing people's stories; trial 3 (June, 2013), general practice endorsement of the programme on the invitation letter; and trial 4 (July–August, 2013) an enhanced reminder letter with a banner that reiterated the screening offer. Socioeconomic status was defined by the Index of Multiple Deprivation score for each home address. The primary outcome was the socioeconomic status gradient in uptake across deprivation quintiles. This study is registered, number ISRCTN74121020.
As all four trials were embedded in the screening programme, loss to follow-up was minimal (less than 0·5%). Trials 1 (n=163 525) and 2 (n=150 417) showed no effects on the socioeconomic gradient of uptake or overall uptake. Trial 3 (n=265 434) showed no effect on the socioeconomic gradient but was associated with increased overall uptake (adjusted odds ratio [OR] 1·07, 95% CI 1·04–1·10, p<0·0001). In trial 4 (n=168 480) a significant interaction was seen with socioeconomic status gradient (p=0·005), with a stronger effect in the most deprived quintile (adjusted OR 1·11, 95% CI 1·04–1·20, p=0·003) than in the least deprived (1·00, 0·94–1·06, p=0·98). Overall uptake was also increased (1·07, 1·03–1·11, p=0·001).
Of four evidence-based interventions, the enhanced reminder letter reduced the socioeconomic gradient in screening uptake, but further reducing inequalities in screening uptake through written materials alone will be challenging.
National Institute for Health Research.
Journal Article