Ahmed
.and here's an example from SRs and meta-analysis (although the outcomes is less objective than 'death'):
Analysis of decisions made in meta-analyses of depression screening and the risk of confirmation bias: A case study
BMC Medical Research Methodology 2012, 12:76 doi:10.1186/1471-2288-12-76
http://www.biomedcentral.com/1471-2288/12/76
Chris Del Mar
From: Evidence based health (EBH) [mailto:[log in to unmask]] On Behalf Of Janet Martin
Sent: Friday, 9 November 2012 7:08 AM
To: [log in to unmask]
Subject: Re: Author Bias and Objective Outcome Measures
Hi Ahmed,
This may be related to what you are looking for:
JAMA. 2004 May 26;291(20):2457-65.
Empirical evidence for selective reporting of outcomes in randomized trials:
comparison of protocols to published articles.
Chan AW, Hróbjartsson A, Haahr MT, Gřtzsche PC, Altman DG.
Centre for Statistics in Medicine, Institute of Health Sciences, Headington,
Oxford, England. [log in to unmask]
CONTEXT: Selective reporting of outcomes within published studies based on the
nature or direction of their results has been widely suspected, but direct
evidence of such bias is currently limited to case reports.
OBJECTIVE: To study empirically the extent and nature of outcome reporting bias
in a cohort of randomized trials.
DESIGN: Cohort study using protocols and published reports of randomized trials
approved by the Scientific-Ethical Committees for Copenhagen and Frederiksberg,
Denmark, in 1994-1995. The number and characteristics of reported and unreported
trial outcomes were recorded from protocols, journal articles, and a survey of
trialists. An outcome was considered incompletely reported if insufficient data
were presented in the published articles for meta-analysis. Odds ratios relating
the completeness of outcome reporting to statistical significance were calculated
for each trial and then pooled to provide an overall estimate of bias. Protocols
and published articles were also compared to identify discrepancies in primary
outcomes.
MAIN OUTCOME MEASURES: Completeness of reporting of efficacy and harm outcomes
and of statistically significant vs nonsignificant outcomes; consistency between
primary outcomes defined in the most recent protocols and those defined in
published articles.
RESULTS: One hundred two trials with 122 published journal articles and 3736
outcomes were identified. Overall, 50% of efficacy and 65% of harm outcomes per
trial were incompletely reported. Statistically significant outcomes had a higher
odds of being fully reported compared with nonsignificant outcomes for both
efficacy (pooled odds ratio, 2.4; 95% confidence interval [CI], 1.4-4.0) and harm
(pooled odds ratio, 4.7; 95% CI, 1.8-12.0) data. In comparing published articles
with protocols, 62% of trials had at least 1 primary outcome that was changed,
introduced, or omitted. Eighty-six percent of survey responders (42/49) denied
the existence of unreported outcomes despite clear evidence to the contrary.
CONCLUSIONS: The reporting of trial outcomes is not only frequently incomplete
but also biased and inconsistent with protocols. Published articles, as well as
reviews that incorporate them, may therefore be unreliable and overestimate the
benefits of an intervention. To ensure transparency, planned trials should be
registered and protocols should be made publicly available prior to trial
completion.
PMID: 15161896 [PubMed - indexed for MEDLINE]
Many thanks,
Janet
____________________________________________________________
Janet Martin, PharmD, MSc(HTA&M)
Director, Medical Evidence*Decision Integrity*Clinical Outcomes (MEDICI)
Assistant Professor, Department of Anesthesia & Perioperative Medicine
Department of Epidemiology & Biostatistics
Schulich School of Medicine & Dentistry
University of Western Ontario
Room C3-172, 339 Windermere Road
London, Ontario
Canada N6A 5A5
email: [log in to unmask]
tel: 519-685-8500 x33031
>>> "Ahmed Abou-Setta, M.D." 11/08/12 3:52 PM >>>
Hello,
I am looking into the issue of ?author bias? especially with the reporting of ?objective outcomes? (e.g. mortality). I know that bias from known sources like sponsorship (e.g. pharmaceutical industry) has been well investigated, but about just purely ?author bias?. Often authors are biased one way or another for a vast number of reasons including but not limited to personal beliefs of efficacy/effectiveness, prior observations in clinical practice, etc. I am looking for publications which measure or test this bias especially for objective outcomes since it?s much easier to bias subjective outcomes (e.g. pain scores) than objective ones (e.g. mortality) especially if the trials were randomized.
Thanks.
Ahmed
P.S. Here is the search strategy I used in PubMed: ("bias (epidemiology)"[MeSH Terms] AND (prejudice[MESH] OR Conflict of Interest[MESH])) NOT Letter [Publication Type]. It yielded some interesting citations but nothing hit the nail on the head.
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