June 2012, Volume 33, Issue 6
Published by AEGIS Communications
The AHA Scientific Statement on Periodontal Disease and ASVD: How Should Clinicians Respond?
The American Heart Association recently issued a Scientific Statement online titled “Periodontal Disease and Atherosclerotic Vascular Disease: Does the Evidence Support an Independent Association?” The statement found conclusions similar to previous literature reviews on the relationship between periodontal disease and cardiovascular disease in that no causative evidence currently exists, but several observational studies indicate that there is an association between the two diseases, independent of shared risk factors. However, some media coverage surrounding the publication of the statement did not accurately recount the statement conclusions.
What led to the inaccurate media reports?
When the AHA published the scientific paper online in Circulation ahead of print, it simultaneously issued a press release that garnered wide media coverage. Unfortunately, a key component of that press release was inaccurate.
The press release stated that previous research showing a periodontitis-cardiovascular disease link failed to control for shared confounders. This statement was inaccurate; many studies, including several cited in the AHA statement, did, in fact, account for shared confounders, independently establishing an association between periodontal disease and cardiovascular disease.
What is an example of an important confounder that needs to be controlled in such studies?
Smoking behavior is a good example of a confounder that can color the results of many studies regarding relationships between different maladies, like the periodontal diseases and cardiovascular disease. If smoking, among other confounders, isn’t properly considered and controlled in such investigations, results may be tainted by an important sampling bias. Regardless, the AHA press release made many good scientists appear sophomoric.
What happened when it became clear that the media coverage was inaccurate?
Organizations such as the American Dental Association (ADA), the American Academy of Periodontology (AAP), the International Association for Dental Research (IADR)/American Association for Dental Research (AADR), and the American Association of Public Health Dentistry all issued their own press releases attempting to clarify the conclusions of the AHA statement. However, the damage had been done—articles relying on the AHA’s mistaken press release appeared almost immediately in the New York Times and in other national media. However, it is my understanding that the AHA has since taken the press release off its website, but as of now it is hard to say what else can be done by the AHA to help fix the problem.
Are there problems with the AHA Statement?
The AHA Statement draws several conclusions. One is that the research-based evidence for or against a periodontitis-cardiovascular disease link is woefully incomplete. In other words, more information is needed from more research. This conclusion is reasonable. However, the article’s singular clinical conclusion went far beyond just a mere recommendation and is worded as a mandate, which is made in the last sentence of the paper that reads: “…statements that imply a causative association between periodontal disease and specific ASVD events or claim that therapeutic interventions may be useful on the basis of that assumption are unwarranted.”
Why is this problematical? Is it wrong?
In the context of what we know and what we don’t know, such a mandate vastly over-reaches what the science says and doesn’t say. However, it is important for clinicians to understand that in most respects the article is a good compilation of the relevant literature. But, such a firm clinical mandate ought not be made in a context of incomplete and conflicting data, especially absent any sort of balanced consideration of costs versus benefits of the clinical options. There are numerous studies that suggest highly plausible associations between periodontitis and adverse cardiovascular effects. Other studies fail to support such links. And, as the AHA Statement accurately recounts, there are no studies that prove a causative or aggravating link between periodontitis and cardiovascular disease.
However, a paucity of high-quality evidence for a link does not mean that there is no link. Indeed a link may be weak, or it may only be important in some patients and not others, thus making it harder to detect. Ambiguous results from systematic reviews typically indicate that better science is needed—a point made in the AHA paper itself.
With regard to cost/benefit analyses, there are always costs incurred by patients and practitioners regarding the choice of an intervention or non-intervention. For example, an intervention costs time, money, etc. A non-intervention can incur costs too, such as the worsening of a health problem. Comparing such costs needs to be part of any patient-oriented decision-making process—even, maybe especially, in situations where there are incomplete data.
To explain this further, let’s look at the article’s abstract. The authors wrote in the abstract: “Patients and providers are increasingly presented with claims that periodontitis treatment strategies offer ASVD protection; these claims are often endorsed by professional and industrial stakeholders.” This suggests that the authors decry the costs associated with advising patients of a link that they seem to believe does not exist. Unfortunately, there is no parallel discussion anywhere in the article regarding the costs likely to be incurred by patients if they are not advised of the link should the link turn out to be real. As I already mentioned, promulgating legitimate clinical recommendations go hand-in-hand with some sort of formal or informal cost-benefit comparisons. Furthermore, a clinical mandate, such as is made by the AHA Scientific Statement, requires a truly compelling cost-benefit argument. This paper does not provide it.
What should clinicians do in response?
Putting patients’ interests above all others, with regard to this or any particular perio-systemic link, I recommend advising patients of what we know and don’t know. In the context of my own opinions about costs versus benefits, I have no problem recommending to a patient that, for example, better oral hygiene and better periodontal health may have small beneficial systemic effects, including with regard to cardiovascular disease. My recommendations reflect what responsible dental professionals, reputable dental organizations, and almost every company in the dental industry have been doing all along. However, shameless promotional efforts along the lines of “floss or die” or “let’s save a life today” are hucksterism, pure and simple. Responsible dental professionals should turn their backs on such carnival acts.
About the Author
Michael P. Rethman, DDS, MS
Periodontist; Adjunct Faculty Member at the University of Maryland and The Ohio State University; former Director of the US Army Institute of Dental Research; Past-President of the American Academy of Periodontology. He recently served 3 years as Chair of the American Dental Association’s Council on Scientific Affairs.