Mammogram Theater: A Visual Aid For Medical Decision-Making

With a title like "mammogram theatre" you would wonder if this post is meant to poke fun at the elaborate song and dance of mammography; we have spent years promising women that "early detection is key," only to realize that screening mammography cannot do what we originally hoped it could (but many still pretend it can).

Of course women want their breasts and lives saved. But the information on the benefits of mammography has been largely overstated in part due to cognitive biases (like lead-time bias, base-rate fallacy, etc), and the risks are too often left out of the conversation.

Every test has risk and benefits, but it can be challenging to decide if a test or treatment is right for you or your patient when there is too much information, experts disagree when they review the same studies, and the media has a constant see-saw back and forth of "yes" and "no" headlines that seem only to confuse. It can feel a bit like ping-pong, following the discussion back and forth. It's not really fair to ask patients to make sense of all this.

So yes, the promise of benefit of mammography may have been a bit of dramatization, but the theatre I speak of is a literal one. 

Dr. Andrew Lazris is an American internist who partnered with environmental scientist Erik Rifkin to popularize a simple, easy way of showing how many are helped and harmed by common tests and procedures.

Lazris and Rifkin have developed a tool to give people a realistic way of evaluating 'hope and worry;'

Their "benefit-risk characterization theater" images vividly show the odds, based on solid research. (read more on NPR)

This is a tool to help doctors and patients have informed discussions about the risks and benefits of breast cancer screening with mammography, to engage in shared-decision making on the topic. Take a look:

This tool has been added to the "hands-on tools" section of this website, where you can find other tools like it.

Source: http://www.npr.org/sections/health-shots/2...

No strong proof that flossing your teeth has medical benefit

This is the third in a series of "no evidence" posts I've made recently, with the first two being "No evidence that N95 respirators are better than surgical masks" and "No benefit to locked mental health wards."

Today's serves as another example of where something seemed like a good idea but... "sURpriSe!!!!" maybe it isn't. 

Certainly, the evidence is lacking to support the bullying that goes on in dental chairs around the world.
"Are you flossing?"
"Yes....."
"Are you sure?"
"Uhhh....." *guilty face*

Personally, as a reluctant flosser, and as a person who questioned the risk/benefit return of having wisdom teeth extracted, I feel a little bit vindicated here. I was always curious 1) if I asked the dentist to guess whether I was flossing or not, could they tell? and 2) Does flossing really do anything useful?

I can't lie to my dentist... how could they do their job if I did? So when asked "have you been flossing?" I usually tell them "no" or "yah but just for 2 months" if I had been doing so, in a phase of thinking I should probably try to stick with flossing. 

Last time I was feeling contemplative in between wafts of chemical smells and *wizzzzzzzes* of the drill in the neighbouring stall, I told my dentist and hygenist that if they could show me solid evidence of benefit of flossing, then I would do it. The hygienist listed a bunch of benefits and I went home to check it out. All the PubMedding in the world didn't find anything to back up her statements. Since they couldn't produce a strong reason for me to do it, so I decided to stop.

Flossing is not fun, it creates waste, and I can think of better things to do with 5 minutes a day. In fact, with those 5 minutes today, I can bring you this article in The Journal of Clinical Peridontology, which found:

The majority of available studies fail to demonstrate that flossing is generally effective in plaque removal. All investigated devices for inter-dental self-care seem to support the management of gingivitis, however, to a varying extent.

The paper did find that  inter-dental brushes (IDBs) are effective in removing plaque. These brushes I have tried and they look like little pipe-cleaners that you shove between your teeth. It feels about as good as it sounds!!! Ow.

I may wait for the randomized controlled trial (RCT) proving that those angry little bristles decrease caries (cavities) before attempting their use again, as "plaque removal" is but a surrogate marker for other things.

Further to the lack of advancement of evidence-based practice in dentistry, one periodontist. Dr Ghilzon, when interviewed by the CBC said:

I would say if you know how to floss I would continue just in case it does make a difference

When the CBC talked to Matthew J. Messina, a dentist and spokesman for the U.S. dental association, they pressed him. He acknowledged weak evidence, but he blamed research participants who didn't floss correctly.

It seems Dentistry is eons behing medicine in terms of evidence gathering let alone application. Whether employing patient-blaming, citing anecdotes, or declining to accept the value of evidence, Dentistry is set to follow Medicine in suffering the same "just in case" approach that dooms patients to overtesting and overtreating and promotes ignorance of the harms of intervention.  

See the original CBC article here.

Source: http://www.cbc.ca/beta/news/health/dental-...

Disutility: Finding the balance between benefit and hassle

James McCormack (@medmyths, The Best Science Medicine Podcast) sent me a great article: "Patient-Accessible Tool for Shared Decision Making in Cardiovascular Primary Prevention."

The UK group looked at the problem of patients discontinuing medication and focussed in particular on statins for primary prevention of cardiovascular events. A lot of research assumes that the 'burden' of taking a pill is a negligible factor in medication adherence, but these researchers thought otherwise. They surveyed 360 people to see how they might balance their potential cardiac risk with the 'disutility' of a preventative, once a day medication as intervention. Paraphrasing, they wanted to know:

how much longer would a person need to live (thanks to a medication) in order to make it worth the hassle of taking the medication

The article is worth sharing because it introduced a few new ideas to me:

  • "disutility" : a word the researchers use to capture the idea of inconvenience or burden of care
  • there is some good evidence that educating people more and more about their risk will not change their adherence to medication
  • talking about reasons they would not want to take the medication may be more important
  • as every person has a different tolerance of disutility, individualized discussions (shared decision-making) still remains a good strategy
  • for people who fall in the middle ground when balancing utility and disutility, factors like gender, smoking, blood pressure, and cholesterol factor into the decision whereas they do not for those with high or low disutility

Figure 4.

Disutility vs utility. Frequency distribution of disutility, longevity benefit that subjects expressed a desire to make tablet therapy worthwhile (top), and the frequency distribution of utility, actual expected gain in lifespan from statin therapy in the English population (bottom). The difference between the 2 values is the net benefit of tablet therapy. Because utility has a very much narrower spectrum than disutility, for those with a high disutility, regardless of utility, statins are a net harm; for those with low disutility, regardless of utility statins are a net benefit. It is only for those in the middle gray zone (top) that sex, smoking status, blood pressure, and cholesterol are the deciding factors.

Read the full article here, in Circulation. 

If you are very interested in the idea of 'disutility,' you may enjoy Dr Victor Montori (@vmontori)'s work on "Minimally Disruptive Medicine."