Entries in Articles (39)


Out-of-Date Systematic Reviews

This paper compares 5 statistical methods for identifying out of date SRs: 

While I'm not going to be running statistical tests to identify out-of-date reviews, knowing that such tests exist might come in handy at some point when chatting w/ researchers. 

[via Evidence-Based Health]

Pattanittum P, Laopaiboon M, Moher D, Lumbiganon P, Ngamjarus C. (2012). A comparison of statistical methods for identifying out-of-date systematic reviews.  PLoS One, 7(11). PMID 23185281 PMC3502410


Differences Between Internal Documentation and Published Results

Interesting study!  The authors (from the summary):

used internal company documents released in the course of litigation against the pharmaceutical company Pfizer regarding the drug gabapentin, to compare between the internal and published reports the reporting of the numbers of participants, the description of the types of analyses, and the definitions of each type of analysis.

to find that there were (also from summary):

several important differences between the internal and published documents about the number of patients included in the analysis

From the paper:

In our sample of industry-supported trials in off-label uses of gabapentin, we observed discrepancies between what was reported in trial publications and what was described in internal company research reports. In this regard, we found that the trial publication was not a transparent, or accurate (presuming that the research report truly describes the facts), record for the numbers of participants randomized and analyzed for efficacy. In three of ten trials in our sample, the number of participants randomized in the trial, as specified in the “main publication” [24],[26],[27], was not the same as that described in the research report. The “main publication” was a full-length journal article for two of the three trials with a disagreement in the number of participants randomized in the trial [24],[26], and a conference abstract describing preliminary results for the third trial [27]. In one case, the description in the publication did not include data from 40% of participants actually randomized in the trial (as described in the research report; see Table 1[26]. There was such wide variation in describing the participant flow in the included trials, even among documents for the same trial, that we were unable to summarize what we found.

We are concerned that, even for commonly used types of analysis such as ITT, a number of different definitions were used across trials included in our sample.

& the authors conclude with recommendations for improved standards and increased transparency.  



Vedula SS, Li T, Dickersin K.  Differences in reporting of analyses in internal company documents versus published trial reports: Comparisons in industry-sponsored trials in off-label uses of gabapentin.  PLoS Med. 2013 Jan;10(1). PMID 2332656 PMC3558476


The Future of Clinical Trial Reporting

From an editorial in PLOS Medicine

So in addition to this being a critical time in the relationship of pharmaceutical companies to society in general, it seems that this is a good time to renegotiate the relationship between pharmaceutical companies and medical journals. As data become more available for reanalysis, the company-sanctioned report of a trial will become less and less the version of record, but instead will become just one part of the metadata around a trial, to be taken in conjunction with all other analyses.

Some journals will find this harder to adjust to than others, especially those whose business model is heavily dependent on reprints of pharmaceutical companies' versions of trial reports. However, journals that are able to successfully migrate into the new world will find a place. Many ways of adding value could be imagined. One is the publishing of multiple, well tagged, easily human- and machine-readable analyses with seamless linking back to the data and protocols, and forward to further analyses. Much of this documentation is already available but is currently proprietary; as Dickersin and colleague note, “Internal company documents provide extensive documentation of methods planned and used, and trial findings, and should be publicly accessible.” These reports will then be of value to systematic reviewers and meta-analysts. Especially critical in these reports will be accurate reporting, such as that championed by the EQUATOR initiative [8].

The PLOS Medicine Editors (2013) Getting More Generous with the Truth: Clinical Trial Reporting in 2013 and Beyond. PLoS Med 10(1): e1001379. doi:10.1371/journal.pmed.1001379


How Effective Are Poster Presentations?

I ask myself this everytime I hover around one of my posters.  The knowledge transfer is probably minimal, but the general networking opportunities are good (I think).  In any case, the article concludes that they're probably not the most effective things in the world:*

Based on current evidence, users should not use a standalone poster in an attempt to achieve knowledge transfer – rather, an integrated approach with supplemental material is required to achieve changes in user knowledge, attitude and behaviour. Well-designed empirical studies are required to establish an evidence base to inform how posters may best be developed and implemented in order to achieve successful knowledge transfer. [PubMed link]

Ilic D, Rowe N. What is the evidence that poster presentations are effective in promoting knowledge transfer? A state of the art review. Health Info Libr J. 2013 Mar;30(1):4-12. PMID 23413789.

* Which I'll no doubt be thinking about during my upcoming poster sessions at CGEA & MLA. (Shameless plug).



Outcome Reporting Bias

And its effect on systematic review outcomes.  Study.

The reliability of systematic reviews, in particular meta-analyses they contain, can be improved if more attention is paid to missing outcome data. The availability of [core outcome sets] for specific health conditions might help with this and the concept has support from the majority of Co-ordinating Editors in [Cochrane review groups].

I seem to be coming across a number of bias in SR papers recently, as well as - not coincidentally, I'm sure - discussions re: the need for better, more consistent reporting. 


Kirkham JJ, Gargon E, Clarke M, Williamson PR. Can a core outcome set improve the quality of systematic reviews? -- a survey of the Co-ordinating Editors of Cochrane review group. Trials. 2013 Jan 22;14(1):21.