There is still controversy about the meaningfulness of HbA1c reduction in diabetics upon non-surgical periodontal therapy. One may get the impression that the number of systematic reviews (SR) on the issue surpasses the number of quality randomized clinical trials (RCT). The most current update by the Cochrane Collaboration (Simpson et al. 2015) had concluded that,
There is low quality evidence that the treatment of periodontal disease by SRP [scaling and root planing] does improve glycaemic control in people with diabetes, with a me an percentage reduction in HbA1c of 0.29% at 3-4 months; however, there is insufficient evidence to demonstrate that this is maintained after 4 months.
I will stick to that statement although I am fully aware that attempts are being made by representatives of our profession of considering rather systematic reviews of SRs as if that would lead to other research outcomes. For still interested readers, I have reported and discussed the issue in numerous blog posts, see e.g. here, here and here.
Treating all kinds of systemic ailments by proper scaling and root planing has been an illusion of certain periodontists for some time. As a healthy antidot, one should carefully read an interview with Jan Lindhe, published some time ago, where he warned us:
I think that the dentist’s area is pretty well described – it’s intraoral and also maxillofacial in a sense but the dentist shouldn’t be a pseudo-doctor for all types of disorders. (Emphasis added.)
After rather devastating negative conclusions made in a systematic review (SR) of the literature regarding the long claimed, possibly causal, relationship between periodontitis and atherosclerotic vascular disease by Lockhart et al. (2012), a highly alerted group of members of our specialty organizations, the Amercian Academy of Periodontology and the European Federation of Periodontology, had hastily organized a joint workshop, in the end of 2012, to fix unwelcome results of a number of large intervention studies by creating new systematic reviews on the Perio-Systemic link. The clear aim was to cement, once and forever, the claim of the number one clinical problem: periodontal disease and general health are closely related.
While the proceedings had been published, open access, in special issues of our main professional journals, the Journal of Clinical Periodontology and the Journal of Periodontology, workshop participants of the EFP presumptuously condensed the 209 pages of the 16, mostly valuable, papers in a nutshell, strangely called Manifesto.
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.