Some discrepancies exist between outcomes indicated in trial registration and later publications

Sep 01, 2009

Comparison of the primary outcomes of registered clinical trials with their subsequent publication appears to show some discrepancies, according to a study in the September 2 issue of JAMA.

In 2005, the International Committee of Editors (ICMJE) adopted a policy requiring researchers to deposit information about randomized controlled trials into a clinical trials registry before study participants enrolled as a precondition for publication of the study's findings in member journals. "One of the main objectives of trial registration is to help achieve transparency in results and make information about the existence and design of clinical trials publicly available," the authors provide as background information. "This policy should permit knowledge sharing about the key elements of clinical trials and help decrease the risk of selective reporting of outcomes that was previously identified in published results of RCTs [randomized controlled trials]."

Sylvain Mathieu, M.D., of Hopital Bichat-Claude Bernard, Paris and colleagues conducted a search of the MEDLINE via PubMed to identify randomized controlled trials in three areas: cardiology, rheumatology, and , that were indexed in 2008 in the 10 general medical journals and specialty medical journals with the highest impact factors. The researchers sought to compare the primary outcomes specified in trial registries with those reported in the published articles and to determine whether outcome reporting bias favored significant primary outcomes. Of the 323 included articles, 114 (35.3 percent) were published in general medical journals and 209 (64.7 percent) in specialty journals.

"A total of 147 trials (45.5 percent) were adequately registered (i.e., registered before the end of the trial, with the primary outcome clearly specified)," the authors write. "Trial registration was lacking for 89 published reports (27.6 percent), 45 trials (13.9 percent) were registered after the completion of the study, 39 (12.1 percent) were registered with no or an unclear description of the primary outcome, and 3 (0.9 percent) were registered after the completion of the study and had an unclear description of the primary outcome." The authors note that the proportion of registered trials was greater for the general medical journals than the specialty publications. "Among articles with trials adequately registered, 31 percent (46 of 147) showed some evidence of discrepancies between the outcomes registered and the outcomes published." Of those 46 articles, the authors report "19 of 23 (82.6 percent) had a discrepancy that favored statistically significant results (i.e., a new, statistically significant primary outcome was introduced in the published article or a nonsignificant primary outcome was omitted or not defined as the primary outcome in the published article)."

"Trial registration provides a good opportunity for editors, peer-reviewers, and policy makers to identify outcome reporting bias, and other deviations from the planned study to prevent such distortions from reaching publication," the authors write.

"In conclusion, although trial registration is now the rule, careful implementation of trial registration, with full involvement of authors, editors, and reviewers is necessary to ensure publication of quality, unbiased results."

More information: JAMA. 2009;302[9]:977-984.

Source: JAMA and Archives Journals (news : web)

Explore further: Experts denounce clinical trials of unscientific, 'alternative' medicines

add to favorites email to friend print save as pdf

Related Stories

Half of trials supporting FDA applications go unpublished

Sep 23, 2008

Over half of all supporting trials for FDA-approved drugs remained unpublished 5 years after approval, says new research published in this week's PLoS Medicine. The most important trials determining efficacy, and those with s ...

Doubts cast on credibility of some published clinical trials

Jul 02, 2009

Randomised Controlled Trials (RCTs) are considered the 'gold standard' research method for assessing new medical treatments. But research published in BioMed Central's open access journal Trials shows that the design of a r ...

Recommended for you

Obese British man in court fight for surgery

Jul 11, 2011

A British man weighing 22 stone (139 kilograms, 306 pounds) launched a court appeal Monday against a decision to refuse him state-funded obesity surgery because he is not fat enough.

2008 crisis spurred rise in suicides in Europe

Jul 08, 2011

The financial crisis that began to hit Europe in mid-2008 reversed a steady, years-long fall in suicides among people of working age, according to a letter published on Friday by The Lancet.

New food labels dished up to keep Europe healthy

Jul 06, 2011

A groundbreaking deal on compulsory new food labels Wednesday is set to give Europeans clear information on the nutritional and energy content of products, as well as country of origin.

Overweight men have poorer sperm count

Jul 04, 2011

Overweight or obese men, like their female counterparts, have a lower chance of becoming a parent, according to a comparison of sperm quality presented at a European fertility meeting Monday.

User comments : 0