Conservative handling of missing information

Berger, Vance W.

doi:10.1016/j.jclinepi.2012.04.017

Cited by 6 publications

(8 citation statements)

References 8 publications

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“…Second, while there are many ways for an RCT planned as blinded to become unblinded, [ 58 ] our study did not use specific mechanisms to look for evidence of unblinding, such as differential (across treatment groups) incidences of specific adverse events that would give away which patients received which interventions and large baseline imbalances indicative of the type of selection bias that may occur with unsuccessful allocation concealment [ 59 , 60 ]. Also, our study did not look at how many RCTs reported a valid and reliable method of assessment of the success of blinding such as the Berger-Exner test of selection bias [ 58 ].…”

Section: Discussionmentioning

confidence: 99%

Influence of blinding on treatment effect size estimate in randomized controlled trials of oral health interventions

Saltaji

Armijo‐Olivo

Cummings

et al. 2018

BMC Med Res Methodol

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BackgroundRecent methodologic evidence suggests that lack of blinding in randomized trials can result in under- or overestimation of the treatment effect size. The objective of this study is to quantify the extent of bias associated with blinding in randomized controlled trials of oral health interventions.MethodsWe selected all oral health meta-analyses that included a minimum of five randomized controlled trials. We extracted data, in duplicate, related to nine blinding-related criteria, namely: patient blinding, assessor blinding, care-provider blinding, investigator blinding, statistician blinding, blinding of both patients and assessors, study described as “double blind”, blinding of patients, assessors, and care providers concurrently, and the appropriateness of blinding. We quantified the impact of bias associated with blinding on the magnitude of effect size using a two-level meta-meta-analytic approach with a random effects model to allow for intra- and inter-meta-analysis heterogeneity.ResultsWe identified 540 randomized controlled trials, included in 64 meta-analyses, analyzing data from 137,957 patients. We identified significantly larger treatment effect size estimates in trials that had inadequate patient blinding (difference in treatment effect size = 0.12; 95% CI: 0.00 to 0.23), lack of blinding of both patients and assessors (difference = 0.19; 95% CI: 0.06 to 0.32), and lack of blinding of patients, assessors, and care-providers concurrently (difference = 0.14; 95% CI: 0.03 to 0.25). In contrast, assessor blinding (difference = 0.06; 95% CI: -0.06 to 0.18), caregiver blinding (difference = 0.02; 95% CI: -0.04 to 0.09), principal-investigator blinding (difference = − 0.02; 95% CI: -0.10 to 0.06), describing a trial as “double-blind” (difference = 0.09; 95% CI: -0.05 to 0.22), and lack of an appropriate method of blinding (difference = 0.06; 95% CI: -0.06 to 0.18) were not associated with over- or underestimated treatment effect size.ConclusionsWe found significant differences in treatment effect size estimates between oral health trials based on lack of patient and assessor blinding. Treatment effect size estimates were 0.19 and 0.14 larger in trials with lack of blinding of both patients and assessors and blinding of patients, assessors, and care-providers concurrently. No significant differences were identified in other blinding criteria. Investigators of oral health systematic reviews should perform sensitivity analyses based on the adequacy of blinding in included trials.Electronic supplementary materialThe online version of this article (10.1186/s12874-018-0491-0) contains supplementary material, which is available to authorized users.

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Section: Discussionmentioning

confidence: 99%

Influence of blinding on treatment effect size estimate in randomized controlled trials of oral health interventions

Saltaji

Armijo‐Olivo

Cummings

et al. 2018

BMC Med Res Methodol

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“…The missing of information in clinical trials could raise a dilemma in the form of two questions to the risk assessors: 1) are we to give them the benefit of the doubt or 2) were the authors strategic in their decision on what items not to describe? [26] Still, it turns out that a large amount of studies with missing information about blinding had in fact performed the blinding [26]. One could argue the suitability to be more conservative with judging missing information [26,27].…”

Section: Discussionmentioning

confidence: 99%

The effect of the CONSORT statement on the amount of “unclear” Risk of Bias reporting in Cochrane Systematic Reviews

Rademaker¹,

Ramakers²,

Smit³

et al. 2020

PLoS ONE

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Background The Consolidated Standards of Reporting Trials (CONSORT) statement aims to improve clarity and consistency of transparency of reporting in Randomized Controlled Trials (RCTs). The Cochrane Risk of Bias (RoB) tool for RCTs helps authors to judge the RoB. as ''low", "high" or "unclear". Objective In this study we aimed to assess whether the implementation and updates of the CONSORT statement influenced the trend of "unclear" RoB scores of RCTs included in Cochrane systematic reviews. Methods All Cochrane reviews published in December to October 2016 were retrieved. The publication year of RCTS included in the reviews were sorted into time frames (�1995, 1996-2000, 2001-2009 and �2010) based on the release-and updates of the CONSORT statement (1996, 2001 and 2010). The association between "unclear" RoB versus "low or high" RoB and the year of publication in different time frames were calculated using a binary logistic regression. Results Data was extracted from 64 Cochrane reviews, with 989 RCTS (6471 items). The logistic regression showed that the odds of RCTs published �2010, compared to �1995 were more likely not to report an "unclear" RoB for the total data (Odds Ratio (OR) 0.69 (95% Confidence interval: 0.59-0.80)), random sequence generation (OR 0.32 (0.22-0.47), allocation concealment (0.64 (0.43-0.95)) and incomplete outcome data (OR 0.60 (0.39-0.91)).

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“…Also, since Figures 1 and 2 3 had no indication of the number of patients that were included in the analysis, we have no way to know if these were ITT analyses or not. We believe clinicians should err on the side of caution when interpreting these results 4 , as the use of ITT analysis, which is often misrepresented, is at best unclear here, and allocation concealment may not have been as 'satisfactory' as the authors 1 claimed. Regarding random sequence generation, we note that there is a precedent 5 for trials labeled as randomized to actually be non-randomized, and we have also already noted that for 70% of the studies, the precise method of randomization was not fully divulged.…”

Section: I a L D I S T R I B U T I O N U N A U T H O R I Z E D U S mentioning

confidence: 94%

Letter to the Editor

Berger

Gudehithlu

2013

Current Medical Research and Opinion

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Conservative handling of missing information

Cited by 6 publications

References 8 publications

Influence of blinding on treatment effect size estimate in randomized controlled trials of oral health interventions

Influence of blinding on treatment effect size estimate in randomized controlled trials of oral health interventions

The effect of the CONSORT statement on the amount of “unclear” Risk of Bias reporting in Cochrane Systematic Reviews

Letter to the Editor

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