To Floss or Not to Floss? That’s not the question

Bioethics-in-the-News-logoThis post is a part of our Bioethics in the News series

By Robyn Bluhm, PhD

Should we stop flossing?
Earlier this month, the Associated Press published a report showing that the evidence in support of flossing is “‘weak, very unreliable,’ of ‘very low’ quality, and carries ‘a moderate to large potential for bias.’” So, should we stop flossing? The American Dental Association says no: “interdental cleaners such as floss are an essential part of taking care of your teeth and gums.”

The AP report and the ADA’s response illustrate interesting questions about evidence-based medicine (EBM), an approach to medical decision-making that has become central to medicine since its introduction in the early 1990s. EBM is often defined as “the conscientious explicit and judicious use of current best evidence in making decisions about the care of individual patients.” The “current best evidence” referred to in this definition is (at least in the case of studies examining treatments) supplied by well-designed randomized controlled trials (RCTs). Although RCTs have been conducted to investigate the effectiveness of flossing, the quality of the studies – and therefore of the evidence they provide – has been poor; this much the AP report and the ADA agree on.

What counts as good evidence? The ADA and EBM
In their response to the report, the ADA appeals to other sources of evidence, ones that EBM considers inferior to RCTs. EBM provides a hierarchy of evidence that ranks research methods according to the quality of evidence they are expected to generate (see, for example, Guyatt et al. 2014, p. 11). At the top of the hierarchy are RCTs, followed by controlled trials that are not randomized. These studies use epidemiological methods to assess treatment outcomes in large groups of patients. Below these study designs comes (1) evidence from physiological research that aims to elucidate the details of biological processes, including the effects of an intervention, and (2) evidence from clinicians’ unsystematic clinical experience, described, for example, in case reports. According to EBM, the first of these lower sources of evidence is problematic because knowledge of physiology does not accurately predict clinical outcomes, while the second source is too limited and small in scale to give generalizable information.

dental floss embroidered in green

Image description: a dental floss package has been embroidered with green thread onto a plain piece of fabric. Image source: Flickr Creative Commons

In fact, the ADA’s response to the report on flossing appeals to both of these “lower” forms of evidence. They begin with an appeal to clinical experience, saying that “As doctors of oral hygiene, dentists are in the best position to advise their patients on oral hygiene practices because they know their patient’s oral health status and history.” The report later endorses the traditional rationale for flossing, which is exactly the kind of physiological reasoning criticized by EBM: “Cleaning between the teeth removes plaque that can lead to cavities or gum disease from the areas where a toothbrush can’t reach. Interdental cleaning is proven to help remove debris between teeth that can contribute to plaque buildup.”

Is the ADA ignoring EBM’s recommended approach to evidence? Not necessarily. Early accounts of EBM seem to recommend strict adherence to the hierarchy of evidence, advising clinicians that “they should look for the highest available evidence from the hierarchy” (Guyatt et al., 2002, p. 8). More recently, this advice has changed to “they should seek the highest-quality evidence available” (Guyatt et al., 2014, p. 11). The problem is that, in the absence of the “best” evidence, well-conducted RCTs, EBM does not provide clear guidance as to how to assess – and act on – the evidence that’s actually available.

What EBM misses…
Despite all of these problems with assessing the evidence, the ADA says that we should just keep flossing. For that matter, (poor evidence alert!) everyone I’ve told about this blog post has said that they don’t plan to stop. And it’s here that a dimension of evidence becomes apparent that is missing in EBM, but is central to bioethics: in deciding whether to use a treatment, we need to consider the balance of benefits and harms. We also need to set our standards of evidence accordingly. Flossing is unlikely to be harmful, and (despite the lack of evidence) may have significant benefits. It is also easy to do and inexpensive, both factors that count on the “benefits” side of the scale. We could try to acquire better evidence to support the ADA’s recommendations, but given how unlikely it is that flossing is actually harmful, we already have enough evidence to justify flossing.

…and why it matters
I suggest that the best way to understand the recent discussion over the evidence for flossing is not as an invitation to rethink our oral hygiene practices, but as an invitation to think more broadly about what kind of evidence, and how much, we should require before we change our health care practices – whether to begin to use a new therapy or to stop using an old one. The “low stakes” in this case may help to illuminate the issues and give us a simple case from which we can begin to think about more complicated questions about values and evidence. And there are plenty of these complicated questions, many of which have also appeared in recent media stories. Consider:

My first response to each of these stories is that I’d want better evidence than I would in the flossing case, in each case because the stakes are higher – both the risks and the potential benefits are greater. But I suspect that there’s no straightforward way to set evidentiary standards based on possible benefits and harms in these cases. I’d welcome readers’ comments on how we might think about the evidence required to decide about these and other complicated cases!

robyn-bluhm-photoRobyn Bluhm, PhD, is an Associate Professor in the Department of Philosophy and Lyman Briggs College at Michigan State University.

Join the discussion! Your comments and responses to this commentary are welcomed. The author will respond to all comments made by Thursday, September 8, 2016. With your participation, we hope to create discussions rich with insights from diverse perspectives.

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Announcing the Fall 2016 Bioethics Brownbag & Webinar Series

bbag-iconThe Center for Ethics and Humanities in the Life Sciences at Michigan State University is proud to announce the 2016-2017 Bioethics Brownbag & Webinar Series, featuring a wide variety of topics from under the bioethics umbrella. The fall series will begin on September 28, 2016, and you can attend the lecture in person or watch live online. Information about the fall series is listed below, and you can visit our website for more details, including the full description and speaker bio for each event.

Fall 2016 Series Flyer

sept28-bbagEthics and Children with Differences in Sex Development and Gender Nonconformity
When should society constrain clinicians from intervening in these contentious arenas?
Wednesday, September 28, 2016
Joel E. Frader, MD, MA, is a Professor of Pediatrics and Professor of Bioethics and Medical Humanities at Northwestern University, and Medical Director of Bridges Pediatric Palliative Care Program at Lurie Children’s Hospital of Chicago.

oct19-bbagChoosing to Test: Dr. A. P. Satterthwaite and the First Birth Control Pill Clinical Trials in Humacao, Puerto Rico
How did Adaline Pendleton Satterthwaite, an obstetrician-gynecologist (OB-GYN) working at a Protestant mission hospital in Puerto Rico, become one of the key architects of the first birth control pill?
Wednesday, October 19, 2016
Kathryn Lankford is a Doctoral Student in the Department of History at Michigan State University.

nov9-bbagTrust and the Learning Health System
What will it take to trust the health system with all that information?
Wednesday, November 9, 2016
Jodyn Platt, MPH, PhD, is an Assistant Professor in the Division of Learning and Knowledge Systems in the Department of Learning Health Sciences at the University of Michigan Medical School.

In person: These lectures will take place in C102 (Patenge Room) East Fee Hall on MSU’s East Lansing campus. Feel free to bring your lunch! Beverages and light snacks will be provided.

Online: Here are some instructions for your first time joining the webinar, or if you have attended or viewed them before, go to the meeting!

Can’t make it? Every lecture is recorded and posted for viewing in our archive. If you’d like to receive a reminder before each lecture, please subscribe to our mailing list.

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New publication from Dr. Fleck in ‘Cambridge Quarterly of Healthcare Ethics’

Leonard Fleck photoAn article from Center Professor Dr. Leonard Fleck was published in the July 2016 issue of Cambridge Quarterly of Healthcare Ethics, “a quarterly journal devoted to engaging a world community of bioethicists.” Dr. Fleck’s article, “Choosing Wisely: Is Parsimonious Care Just Rationing?” accesses claims related to the practices of rationing and parsimonious care.

Abstract: The American College of Physicians in its ethics manual endorsed the idea that physicians ought to improve their ability to provide care to their patients more parsimoniously. This elicited a critical backlash; critics essentially claimed that what was being endorsed was a renamed form of rationing. In a recent article, Tilburt and Cassel argued that parsimonious care and rationing are ethically distinct practices. In this essay I critically assess that claim. I argue that in practice there is considerable overlap between what they term parsimonious care and what they define as rationing. The same is true of the Choosing Wisely campaign endorsed by the American Board of Internal Medicine. In both cases, if the goal is to control healthcare costs by reducing the use of marginally beneficial care that is not cost effective, then a public conversation about the justness of specific choices is essential.

To read Dr. Fleck’s article in full, please visit the Cambridge Quarterly website.

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Dr. Stahl presents at International Academy for Bioethical Inquiry Summer Symposium

stahl-crop-2015Center Assistant Professor Dr. Devan Stahl recently presented at the International Academy for Bioethical Inquiry (IABI) Summer Symposium, held August 8-10 at Saint Louis University’s Albert Gnaegi Center for Health Care Ethics.

Dr. Stahl presented the paper “The Fate of Disabled Bodies in a Posthuman Future.” Her presentation explored themes of disability, Christianity, and transhumanism.

Please visit our website to learn more about Dr. Stahl’s work.


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Dr. Cabrera published in ‘Sociological Methods & Research’

cabrera-crop-2015Center Assistant Professor Dr. Laura Cabrera was recently published in the journal Sociological Methods & Research. The article, “A Novel Sequential Mixed-method Technique for Contrastive Analysis of Unscripted Qualitative Data: Contrastive Quantitized Content Analysis,” was co-authored by Dr. Cabrera and Peter B. Reiner of the National Core for Neuroethics at University of British Columbia. The article was published online ahead of print on August 4, 2016.

Abstract: Between-subject design surveys are a powerful means of gauging public opinion, but critics rightly charge that closed-ended questions only provide slices of insight into issues that are considerably more complex. Qualitative research enables richer accounts but inevitably includes coder bias and subjective interpretations. To mitigate these issues, we have developed a sequential mixed-methods approach in which content analysis is quantitized and then compared in a contrastive fashion to provide data that capitalize upon the features of qualitative research while reducing the impact of coder bias in analysis of the data. This article describes the method and demonstrates the advantages of the technique by providing an example of insights into public attitudes that have not been revealed using other methods.

The full text is available on the Sociological Methods & Research website (note: institutional access, such as access through Michigan State University Libraries, may be required to view the full text).

Dr. Cabrera is a faculty affiliate in the National Core for Neuroethics at University of British Columbia.

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Drs. Kelly-Blake and Holmes-Rovner co-authors of shared decision making article

Kelly-BlakeHolmes-RovnerCenter Assistant Professor Dr. Karen Kelly-Blake and Professor Emerita Dr. Margaret Holmes-Rovner are among the co-authors of the article “Implementing shared decision making in federally qualified health centers, a quasi-experimental design study: the Office-Guidelines Applied to Practice (Office-GAP) program,” published on August 2, 2016 in the open-access journal BMC Health Services Research. The study was authored by MSU researchers Adesuwa Olomu, William Hart-Davidson, Zhehui Luo, Karen Kelly-Blake and Margaret Holmes-Rovner.

Background: Use of Shared Decision-Making (SDM) and Decision Aids (DAs) has been encouraged but is not regularly implemented in primary care. The Office-Guidelines Applied to Practice (Office-GAP) intervention is an application of a previous model revised to address guidelines based care for low-income populations with diabetes and coronary heart disease (CHD). Objective: To evaluate Office-GAP Program feasibility and preliminary efficacy on medication use, patient satisfaction with physician communication and confidence in decision in low-income population with diabetes and coronary heart disease (CHD) in a Federally Qualified Healthcare Center (FQHC).

The full article is available on the BMC Health Services Research website.

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Libby Bogdan-Lovis published in ‘AIDS Patient Care and STDs’

bogdanlovis-crop-facCenter Assistant Director Libby Bogdan-Lovis co-authored the article “‘‘She Told Them, Oh That Bitch Got AIDS’’: Experiences of Multilevel HIV/AIDS-Related Stigma Among African American Women Living with HIV/AIDS in the South,” published in the July 2016 issue of AIDS Patient Care and STDs.

The article, authored by Faith Fletcher, PhD, MA, Lucy Annang Ingram, PhD, MPH, Jelani Kerr, PhD, MSPH, Meredith Buchberg, MPH, Libby Bogdan-Lovis, and Sean Philpott-Jones, PhD, MSB, uses narrative data to explore the stigma that HIV-positive African American women living in the southern United States face in their daily lives. The text is available in full on the AIDS Patient Care and STDs website.

Abstract: African American women bear a disproportionate burden of HIV/AIDS in the United States. Although they constitute only 13% of the US population, African Americans account for nearly 65% of all new HIV infections among American women. In addition, this population suffers comparatively greater adverse health outcomes related to HIV status. African American women living with HIV in the South may be further burdened by HIV/AIDS stigma, which is comparatively more pronounced in this region. To further explore this burden, we used narrative data and the Social Ecological Model to explore how African American women living with HIV in the US South recount, conceptualize, and cope with HIV/AIDS stigma at interpersonal, community, and institutional levels. Our narrative analysis suggests that HIV-positive African American women living in the South are vulnerable to experiences of multilevel HIV stigma in various settings and contexts across multiple domains of life. Stigma subsequently complicated disclosure decisions and made it difficult for women to feel supported in particular social, professional and medical settings that are generally regarded as safe spaces for noninfected individuals. Findings suggest that the debilitating and compounded effect of multilevel HIV/AIDS stigma on HIV-positive African American women in the South warrants closer examination to tailor approaches that effectively address the unique needs of this population.

To learn more about Dr. Faith Fletcher’s work in this area, visit our webinar archive to watch her lecture “Ethical Implications of HIV Pre-Exposure Prophylaxis (PrEP) for African American Women and Adolescent Girls,” recorded in February 2016 as part of our Bioethics Brownbag & Webinar Series.

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