In a recent analysis of thousands of randomized controlled trials (RCT) in eight journals a simple method was offered which might enable skeptical scientist identification of data fabrication. Editor of the Anaesthesia journal John B. Carlisle of Torbay Hospital, UK, looked at baseline differences of means in more than 5000 randomized controlled trials, mainly in the field of Anesthesiology, but also more than 500 published in JAMA and more than 900 published in the New England Journal of Medicine . His study went online earlier this week. Analyzed articles were published between 2000 and 2015. In brief, if randomization was successful, baseline differences should be small. Giving p-values for baseline differences (in order to indicate successful randomization) is actually discouraged since they are not really interpretable, but Carlisle calculated them anyway. If the null hypothesis is true, p-values have a uniform distribution. So p-values between 0 and 1 would be equally likely.
Claims and denials of clinically relevant effects of, in particular, non-surgical periodontal treatment on markers of diabetic control have not only led to a surge of new randomized clinical trials and systematic reviews thereof. If anybody had hope that the current frenzy has found a happy end with the updated and very comprehensive Cochrane review by Simpson et al. (2015) (s)he has been mistaken. In the June issue of the Australian Dental Journal, Botero et al. (2016) report on an umbrella review in which they systematically reviewed all systematic reviews on the subject, be it with or without meta-analysis, published between 1995 and 2015. The paper has been accepted for publication on January 20, 2016. It has to be emphasized that using the term “umbrella review” is somewhat misleading. In a strict sense, an umbrella review assembles together several systematic reviews on the same condition in the presence of many treatments or many important outcomes.
In a previous post, I have expressed considerable concern about an assumed advertorial in our leading periodontal journal, JCP. Quintessence Publishing was about to launch their fourth installment of “3D” animated, short (each 15-17 min) movies all called Cell-to-Cell Communication, “Oral Health and General Health – The Links between Periodontitis, Atherosclerosis, and Diabetes.” Previous movies have been offered for purchase by QuintPub for a remarkable amount of around $100. Luckily, the new one can now be found on the EFP homepage and accessed by members and non-members for free.
It is remarkable that the prestigious Journal of Clinical Periodontology, founded by Hans Mühlemann and edited for decades by Jan Lindhe, is going to publish a commercial for a Quintessence Publishing and Sunstar production, part of a Quintpub series of DVDs (all called Cell-to-Cell Communication) of short (each runs for about 15 minutes) animated (“3D”) movies. The first installations in this series had been about inflammatory reactions in the periodontium (I had critically reported on its educational value here), periodontal regeneration and osseointegration.
The first withdrawn manuscript by Drs. Wenche Borgnakke and Iain Chapple and each and every editor of our hardcore periodontal journals as well as otherwise eminent individual in Periodontology, which had proclaimed that “[t]he randomized controlled trial (RCT) published by the Journal of the American Medical Association (JAMA) on the impact of periodontal therapy on glycated hemoglobin (HbA1c) has fundamental flaws” about the paper by Engebretson et al. (2013), see [pdf], went online today in the Journal of Evidence-Based Dental Practice.
I had wondered before why it had been withdrawn but couldn’t figure that out. Interesting may be that the withdrawn paper had listed all 19 authors, while the current version does not. Maybe that Borgnakke and Chapple are only pawns in a worldwide political enterprise launched by our “thought leaders”. It may also be that more “evidence” (see below), possibly (but rather not) suitable for putting findings by Engebretson et al. (2013) into perspectve, needed to be included in what is almost a revile.