Our results highlight a tendency for press releases and the associated media coverage of RCTs to place emphasis on the beneficial effects of experimental treatments. This tendency is probably related to the presence of “spin” in conclusions of the scientific article's abstract. This tendency, in conjunction with other well-known biases such as publication bias, selective reporting of outcomes, and lack of external validity, may be responsible for an important gap between the public perception of the beneficial effect and the real effect of the treatment studied.
Previous studies have highlighted the importance of press releases for results communication and dissemination 
. Indeed, as a direct means of communication between medical journals and the media, press releases provide an opportunity for journals to influence how the research is translated into news 
. The press release is essential when considering the impact of press coverage by the media on health care utilization, clinical practice, and researchers' behavior 
. This influence has been clearly shown in a quasi-experimental study evaluating the impact of media coverage 
. The authors compared the number of scientific citations of articles published in the New England Journal of Medicine
that were covered by the New York Times
to similar articles that were not covered. They also performed this comparison during a 3-mo period when the New York Times
was on strike; the New York Times
continued to print an “edition of record” but did not sell copies to the public because of the strike. The authors demonstrated that the high citation of articles covered by the New York Times
was not present during the strike. Consequently, the high citation was related to the media coverage, not the importance of the research 
. A Cochrane systematic review highlighted the impact of the mass media on health services utilization 
. It showed a consistent effect after planned campaigns and unplanned coverage. Another study showed a clear association of the media coverage of invasive group A streptococcal (GAS) disease and testing for GAS in pediatric emergency departments, with an important increase in the prescription of rapid tests for GAS in pediatric emergency departments concomitant with a peak in media attention, despite no increase in the number of children presenting symptoms that might warrant such testing 
Unfortunately, as shown in our study, and previous work the quality of media reports is questionable. An assessment of the reporting of medical news in the mainstream media highlighted the inadequate accuracy and balance of the news media in reporting medical science 
. The criticisms of the mainstream media also applied to press releases. Woloshin et al., in evaluating press releases issued by 20 academic medical centers, showed that the releases frequently promoted preliminary research without giving basic details or the cautions needed to judge the meaning, relevance, or validation of the science (42% of press releases evaluated in this study did not provide any relevant caveats, and 90% about animal or laboratory studies lacked caveats about extrapolating results to humans) 
. Furthermore, press releases tended to overstate the importance of the research, 29% were rated as exaggerating the findings' importance and 26% of investigator quotes were considered to overstate the research importance 
. Recently, a study showed that the quality of press releases influenced subsequent media coverage content 
Of course, press releases are not meant to be condensed versions of scientific papers; they are meant to summarize the most important findings, contextualize these finding for journalists, and provide contact details for authors and quotes. By being condensed, they always lack details that are contained in the papers. The use of “spin” or a particular emphasis could be a way to increase the interest of journalists and subsequent citations in the peer-reviewed literature.
However, this situation becomes problematic if it modifies readers' interpretation of research findings. Our results add to these previous studies by showing the link between the distorted presentation and interpretation of the results in scientific articles and the distorted content and interpretation of press releases. These findings raise the issue of the quality of the peer review process and highlight the importance of this process for disseminating accurate research results.
Our study has several limitations. Firstly, our sample included only published reports of RCTs with a press release indexed in the Eurekalert! database within a 4 mo period, and reported in English; this sample may not be representative of all press releases of RCT results. In fact, half of the press releases selected were written by press officers of medical journals with a high impact factor. Other sources of press releases exist on industry websites, medical journal websites, or other databases for journalists. However, the Eurekalert! database is one of the most important sources of freely available press releases, and most research published on press releases has used this database. Further, there is no reason to believe that the selection of the sample over only 4 mo would bias the results. Secondly, RCTs represent only a small part of the medical literature and the findings may not apply to media reporting of medical or scientific research as a whole. Thirdly, we searched for “spin” only in the article abstract conclusions, not in the entire published article. Consequently, we are not able to determine whether “spin” in the press release was the same as the “spin” in the whole article. We chose the abstract conclusions because it is the most accessible section of an article. Readers often base their initial assessment of a trial on the information reported in an abstract conclusion, and in some geographic areas, the abstract of an RCT report may be all that health professionals have easy access to 
. Fourthly, the content analysis and the interpretation coding were subjective 
. However, two independent reviewers performed this assessment with consensus. Fifthly, we focused on articles and press releases of RCT results. We did not evaluate press releases for other study designs or proceedings of conferences.
In conclusion, previous work showed that exaggerated and inappropriate coverage of research findings in the news media is linked to inappropriate reporting of press releases. Our study adds to these results showing that “spin” in press releases and the news is related to the presence of “spin” in the published article, namely the abstract conclusions. Additionally, our work highlights that this inappropriate reporting could bias readers' interpretation of research results.
Consequently, reviewers and editors of published articles have an important role to play in the dissemination of research findings and should be particularly aware of the need to ensure that the conclusions reported are an appropriate reflection of the trial findings and do not overinterpret or misinterpret the results.