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Archive for December, 2009

The Mammogram Post-Mortem

The Mammogram Post Mortem
Steve Novella whimsically opined on a recent phone call that irrationality must convey a survival advantage for humans. I’m afraid he has a point.
It’s much easier to scare people than to reassure them, and we have a difficult time with objectivity in the face of a good story. In fact, our brains seem to be hard wired for bias – and we’re great at drawing subtle inferences from interactions, and making our observations fit preconceived notions. A few of us try to fight that urge, and we call ourselves scientists.
Given this context of human frailty, it’s rather unsurprising that the recent USPSTF mammogram guidelines resulted in a national media meltdown of epic proportions. Just for fun, and because David Gorski nudged me towards this topic, I’m going to review some of the key reasons why the drama was both predictable and preventable.  (And for an excellent, and more detailed review of the science behind the kerfuffle, David’s recent SBM article is required reading. http://www.sciencebasedmedicine.org/?p=1926 )
Preamble
In an effort to increase early detection of breast cancer, American women have been encouraged to get annual screening mammograms starting at age 40. Even though mammograms aren’t as sensitive and specific as we’d like, they’re the best screening test we have – and so with all the caveats and vagaries associated with what I’d call a “messy test,” we somehow collectively agreed that it was worth it to do them.
Now, given the life-threatening nature of breast cancer, it’s only natural that advocacy groups and professional societies want to do everything in their power to save women from it. So of course they threw all their weight behind improving compliance with screening mammograms, and spent millions on educating women about the importance of the test. Because, after all, there is no good alternative.
However, the downside of an imprecise test is the false positive results that require (in some cases) invasive studies to refute them.  And so this leaves us with 2 value judgments:  how many women is it acceptable to harm (albeit it mildly to moderately) in order to save one life? Roughly, the answer is a maximum of 250 over 10 years (I came up with that number from the data here: http://www.sciencebasedmedicine.org/?p=565 if as many as half of women receive a “false alarm” mammogram over a period of 10 years of testing, and half of those undergo an unnecessary biopsy). And second: how many tests are we willing to do (this is more-or-less an economic question) to save 1 life? The answer is roughly 1900.
So when the USPSTF took a fresh look at the risks and benefits of mammography and recommended against screening average risk women between 40-50 (and reducing mammogram frequency to every other year for those over 50), what they were saying is that they would rather injure fewer women and do fewer costly tests for the trade off of saving fewer lives. In fact, their answer was that they were willing to perform 1300 mammograms to save 1 life, not 1900 (as has been our standard of care).
This value judgment is actually not, in and of itself, earth shattering or irresponsible. But it’s the societal context into which this judgment was released that made all the difference.
1. Timing Is Everything: Or, why not to bring a party hat to a funeral
First of all, it’s almost amusing how bad the timing of the USPSTF guidelines really were. The country was in the midst of trying to pass our country’s first serious healthcare reform bill in decades (at least, the house reform bill was being voted upon the week that the USPSTF guidelines were released) and opponents of the bill had already expressed vehement concern about arbitrary government rationing of healthcare services.
What worse time could there have been to announce that a government agency is (against the commonly held views of the rest of the medical establishment) recommending reduction in frequency  of a life-saving screening test for women? The fact that the guidelines leader said she hadn’t thought about the greater context when she scheduled the press release is quite astonishing. On the one hand, I suppose it shows how disconnected from potential political bias the workgroup really is. On the other hand, it is violates Public Relations 101 so completely as to call into question the judgment of those making… er… judgments.
2. You Can’t Replace Something With Nothing: Or How To Take Scissors From A Baby
Let’s just say for a moment that we all agree that mammograms aren’t the greatest screening test for breast cancer. They’re rather expensive, and wasteful perhaps one might even argue that in a healthcare system with limited resources, one healthy woman’s screening test is another woman’s insulin.  But – it’s all we have. And they do save lives… occasionally.
Anyone who’s seen a child pick up something harmful realizes that the only way to take it from them without tears is to replace it with something harmless. You can’t just take away mammograms from women who have come to expect it, without offering them something more sensible. If there is nothing, then I’m afraid that discontinuing them will result in considerable outrage which you may or may not wish to engage. Given the size and power of the breast lobby – I’d say it’s pretty much political suicide.
3. Know Your Opposition: Or Don’t Bring A Knife To A Gun Fight
And that brings me to point #3. The breast cancer movement is one of the most powerful and successful disease fighting machines in the history of medicine. And bravo to all the women and men who made it such a visible disease. The amount of funding, research, and PR that this cancer gets is astounding – it dwarfs many other worthy diseases (like pancreatic cancer or lymphoma), and is a force to be reckoned with.
Which is why, before you undermine a cherished tenet of such a group, you take a long hard look at what you’re going to say… Because it will be shouted from the hilltops, scrutinized from every conceivable angle, and used to rally all of Hollywood, the medical establishment, and everyone in Washington to its cause. Yeah, you better be darn sure you’re “right” (whatever that means in this context) before attempting to promote a service cut back to this group.
4. Know Who You Are: Or Unilateral Decision Making Is Not A Great Idea – Especially For Government
And finally, it’s important not only to know who you’re dealing with, but to know your mission in society so you can be maximally effective. The US government exists to honor the will of the people and serve its citizens. The best way to do that is to listen to them carefully, engage in consensus-building, and try to be a good steward of resources. When government behaves in ways counter to our expectations, it provokes some legitimate negativity.
So, for example, when a small group of civil servants hole themselves up in a room to create guidelines that will potentially take preventive health services away from women – resulting in a larger number of deaths each year… and they don’t invite input from key stakeholders, and announce their views in the midst of a firestorm about “rationing”
In summary
The new USPSTF guidelines for mammogram screenings debacle serves as a perfect public relations case study in what not to do in advancing healthcare reform. It was the perfect storm of high profile subject, bad timing, poor argument preparation, and lack of back up planning. Though we could have had a rational discussion about the cost/benefit analysis of this particular screening test, what we got instead was the appearance of a unilateral rationing decision by an out-of-touch government organization, devaluing women to the point of death. Throw that chum in the water of human frailty and you’ll get the same result every time: a media feeding frenzy that makes you regret the moment that guideline development became a twinkle in your task force eye.

Steve Novella whimsically opined on a recent phone call that irrationality must convey a survival advantage for humans. I’m afraid he has a point.

It’s much easier to scare people than to reassure them, and we have a difficult time with objectivity in the face of a good story. In fact, our brains seem to be hard wired for bias – and we’re great at drawing subtle inferences from interactions, and making our observations fit preconceived notions. A few of us try to fight that urge, and we call ourselves scientists.

Given this context of human frailty, it’s rather unsurprising that the recent USPSTF mammogram guidelines resulted in a national media meltdown of epic proportions. Just for fun, and because David Gorski nudged me towards this topic, I’m going to review some of the key reasons why the drama was both predictable and preventable.  (And for an excellent, and more detailed review of the science behind the kerfuffle, David’s recent SBM article is required reading.)

(more…)

Posted in: Cancer, Public Health, Science and the Media

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Midwives and the assault on scientific evidence

The new mantra of midwives and their advocates is “evidence based practice.” Lamaze, the childbirth education organization has changed the name of their blog to “Science and Sensibility” emphasizing the importance of science and promising:

Lamaze education and practices are based on the best, most current medical evidence available, and can help reduce the overuse of unnecessary interventions while improving overall outcomes for mothers and babies.

But midwives and childbirth educators like Lamaze have a problem. The scientific evidence often conflicts with their ideology. They could address this problem in several ways. Midwives could modify their specific ideological beliefs on the basis of scientific evidence. Childbirth educators could question whether ideology has had an inappropriate impact on the promulgation and validation of their recommendations. Both those approaches would involve a threat to cherished beliefs. They, therefore, have taken a different approach. They’ve tried to justify ignoring scientific evidence.

As midwives Jane Munro and Helen Spiby have documented in The Nature and Use of Evidence in Midwifery, the first chapter of their book Evidenced Based Midwifery, midwives were initially enthusiastic about basing clinical practice on scientific evidence. That’s because they had long told each other that midwifery was “science based” while obstetrics was not:

At the beginning of the evidence based practice movement, much of the midwifery profession responded enthusiastically to the potential for change… Evidence based practice was seen to be offering a powerful tool to question and examine obstetric-led models of care that had dominated the previous decades. The results of such examination could have meant ‘starting stopping’ the unhelpful interventions that had embedded themselves in common practice …

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Posted in: Obstetrics & gynecology

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Evidence in Medicine: Experimental Studies

Several weeks ago I wrote the first in a brief series of posts discussing the different types of evidence used in medicine. In that post I discussed the role of correlation in determining cause and effect.

In this post I will discuss the basic features of an experimental study, which can sere as a check-list in evaluating the quality of a clinical trial.

Medical studies can be divided into two main categories – pre-clinical or basic science studies, and clinical studies. Basic science studies involve looking at how parts of the biological system work and how they can be manipulated. They typically involve so-called in vitro studies (literally in glass) – using test tubes, petri dishes, genetic sequencers, etc. Or they can involve animal studies.

Clinical trials involve people. They are further divided into two main categories – observational studies and experimental studies. I will be discussing experimental studies in this post – studies in which an intervention is done to study subjects. Observational studies, on the other hand, look at what is happening or what has happened in the world, but does not involve any intervention.

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Posted in: Science and Medicine

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Acupuncture for Chronic Prostatitis/Chronic Pelvic Pain Syndrome

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is a somewhat nebulous diagnosis with unknown etiology and no effective treatment. To make the diagnosis, bacterial infection must be excluded and the symptoms must last at least 3 months. Symptoms include pain in various locations (between rectum and testicle, in the testicles, at the tip of the penis, in the lower back, in the abdomen over the pubic or bladder area), pain or burning with urination, frequent urination, pain or discomfort during or after sexual climax. There are also systemic features like decreased libido, myalgias, and fatigue, and there is a higher incidence of chronic fatigue syndrome in these patients. The connection to the prostate is uncertain; in one study, women with chronic pelvic pain reported more of these symptoms than men did. Diagnosis is based on self-reported symptoms; there are no objective diagnostic markers. Somewhere between 2 and 10% of the male population are reported to suffer from this syndrome.

Since there is no effective mainstream treatment for this disorder, why not try acupuncture? Two randomized, placebo-controlled studies have reported positive results from acupuncture treatment. Is this enough evidence for us to recommend it to patients? (more…)

Posted in: Acupuncture

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Endocrine disruptors—the one true cause?

A common theme in alternative medicine is the “One True Cause of All Disease”. Aside from the pitiable naivete, it’s implausible that “acidic diet”, liver flukes, colonic debris, the Lyme spirochete, or any other problem—real or imagined—can cause “all disease” (in addition to the fact that most of these ideas are intrinsically mutually exclusive).

One of the popular new ideas in this category is that of “endocrine disrupting chemicals” (EDCs). These are chemicals in the environment that physiologically or chemically mimic naturally occurring human hormones. That some environmental substances are chemically similar to human hormones is indisputable. That these substances can have a real physiologic effect in vitro seems to hold up. How much of an effect these chemicals may have in real human populations is an open question.

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Posted in: Science and Medicine, Science and the Media

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Yet another nail in the coffin of the myth that the MMR vaccine causes autism

Arguably, the genesis of the most recent iteration of the anti-vaccine movement dates back to 1998, when a remarkably incompetent researcher named Andrew Wakefield published a trial lawyer-funded “study” in the Lancet that purported to find a link between “autistic enterocolitis” and measles vaccination with the measles-mumps-rubella (MMR) trivalent vaccine. In the wake of that publication was born a scare over the MMR that persists to this day, 11 years later. Although peer reviewers forced the actual contents of the paper to be more circumspect, in the press Wakefield promoted the idea that the MMR vaccine either predisposes, causes, or triggers autistic regressions. Even though over the next several years, investigations by investigative journalist Brian Deer revealed that not only was Wakefield’s research funded by trial lawyers looking to sue vaccine manufacturers for “vaccine injury” when he did his research (for which he is now being charged by the U.K.’s General Medical Council with scientific misconduct), but during the Autism Omnibus trial testimony by a world-renowed expert in PCR technology showed that he was incompetent. Even worse for Wakefield, in February 2009 Brian Deer published a news expose based on strong evidence that Wakefield may very well have falsified data for his Lancet paper.

None of this mattered. Andrew Wakefield still enjoys a cult of personality among the anti-vaccine crowd that no revelation seems able to dislodge, even the revelation that at the time he was both in the pay of trial lawyers and working on his study, Andrew Wakefield was also applying for a patent for a rival measles vaccine. Indeed, the anti-vaccine propaganda blog Age of Autism bestowed upon him last year its “Galileo Award” as the “persecuted” scientist supposedly fighting for truth, justice, and anti-vaccinationism against the pharma-funded or brainwashed minions of the “Church of the Immaculate Vaccination.” In the meantime, MMR uptake rates in the U.K. have plummeted over the last decade, far below the level needed for herd immunity, to the point where, last year the Health Protection Agency declared measles to be once again endemic in the U.K., 14 years after the local transmission of measles had been halted.

Since Wakefield’s study was released, a number of studies have shown that there is no epidemiologically detectable link between vaccination with MMR and autism, including one by a researcher who once appeared to be a believer in the idea that vaccines are somehow linked with autism, Mady Hornig. Hornig actually tried very hard to replicate Wakefield’s 1998 Lancet study, only this time with more children, and she found no link between MMR and autism using methodology similar to Wakefield’s. None of these studies has had any effect on the anti-vaccine movement, except to motivate them to circle the wagons even more, as J.B. Handley of Generation Rescue did when he launched a website called Fourteen Studies, whose purposes are to launch fallacious and pseudoscientific attacks on studies failing to find a link between vaccines and autism (often involving accusations of being a “pharma shill”), to promote the lousy science that gives the appearance of supporting the hypothesis that there is a link between the MMR vaccine and autism, and then slime anyone who points out how deceptive their attacks were.

Now, yet another study has been released studying whether there is a link between MMR vaccination and autism. Yet another study has failed to find a link between MMR vaccination and autism. Yet another study is all set to be attacked by Generation Rescue and the anti-vaccine movement. The sad and sordid history of reactions of the anti-vaccine movement to studies that do not support its belief in the unsinkable rubber duck of a myth that vaccines cause autism. This study was published online in The Pediatric Infectious Disease Journal by a group from Department of Epidemiology and Preventive Medicine, Jagiellonian University, Collegium Medicum, Krakow, Poland (a Polish group, my people!) and entitled Lack of Association Between Measles-Mumps-Rubella Vaccination and Autism in Children: A Case-Control Study. It’s yet another nail in the coffin of the myth that the MMR causes or contributes to autism. Indeed, this study not only shows that MMR vaccination is not associated with autism but that it may even be protective against autism. True, for reasons I will discuss shortly, I doubt that that latter interpretation is true, but there’s no doubt that this study is powerful evidence against the view that there is an association between MMR and autism. Unfortunately, I fear that all the nails in my local Home Depot would not be enough to keep the zombie of this pseudoscience from rising from its grave yet again.
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Posted in: Clinical Trials, Vaccines

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Lose those holiday pounds

Lose weight without diet or exercise? I guess that leaves cancer.

–David Letterman.

It is the day after Thanksgiving, and I have probably eaten enough calories to support the average family for at least three days. I am hesitant to comment on what my actual weight may be, but others have not been so reticent about discussing my appearance over at RDCT. At least I am not female; then I would get no end of critiques based on my looks.

Now that I am up a few holiday pounds, it would be nice to lose some weight. Of course I do not want to do it the old fashioned way, with diet and exercise. Diet and exercise take time and are fundamentally painful. I want to eat what I want when I want from the comfort of my Lazy Boy. I want an easy way to lose weight. The interwebs, as is often the case, have been kind enough to provide me with numerous emails suggesting all sorts of simple ways to alter my physique for the better, some of which even include weight loss.

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Posted in: Science and Medicine

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A critique of the leading study of American homebirth

Its authors boast that it is one of the ten most downloaded papers from the British Medical Journal (BMJ). That makes it even more unfortunate that the conclusions of the paper are directly at odds with the findings of the paper. Outcomes of planned home births with certified professional midwives: large prospective study in North America by Kenneth Johnson and Bettye Ann Davis is the premier paper on the safety of American homebirth. It claims to show that homebirth is as safe as hospital birth, but actually shows that homebirth has nearly triple the neonatal death rate of hospital birth for comparable risk women.

Johnson and Daviss, in collaboration with the Midwives Alliance of North America (MANA), the organization of American homebirth midwives, collected data on all homebirths attended by Certified Professional Midwives (CPMs, homebirth midwives, as distinct from CNMs, Certified Nurse Midwives) in the year 2000. Then the authors compared the outcomes for interventions and for neonatal deaths with a hospital group.

According to Johnson and Davis, when analyzing the different intervention rates of home and hospital:

We compared medical intervention rates for the planned home births with data from birth certificates for all 3 360 868 singleton, vertex births at 37 weeks or more gestation in the United States in 2000, as reported by the National Center for Health Statistics [Births: final data for 2000. National vital statistics reports. Martin JA, Hamilton BE, Ventura SJ, Menacker F, Park MM. Hyattsville, MD: National Center for Health Statistics, 2002;50(5)]

They used singleton, vertex births at 37+ weeks as a proxy for low risk women. They found, not surprisingly, that intervention rates are lower for homebirth. Then they turned to neonatal mortality rates. They should have compared the neonatal mortality rate of the homebirth group to the neonatal mortality rate of the hospital birth group, but they did not. Instead, they compared homebirth deaths to hospital births in a variety of out of date studies extending back more than 20 years.

The authors conclude:
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Posted in: Obstetrics & gynecology

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A temporary reprieve from legislative madness

While doctor visits for influenza-like illnesses seem to be trending downward again, and ”swine flu” is becoming old news, I’d like to draw attention to an H1N1 story that has received very little coverage by the mainstream media.

Doctors in several states can now protect their most vulnerable patients from the H1N1 virus without worrying about breaking the law. In order to save lives, several states have announced emergency waivers of their own inane public health laws, which ban the use of thimerosal-containing vaccines for pregnant women and young children.

Legislators in California, New York, Illinois, Missouri, Iowa, Delaware, and Washington state have enacted these science-ignoring laws in response to pressures from the anti-vaccine lobby and fear-struck constituents. Except for minor differences, each state’s law is essentially the same, so I will focus on the one from my state of New York.

New York State Public Health Law §2112 became effective on July 1, 2008. It prohibits the administration of vaccines containing more than trace amounts of thimerosal to woman who know they are pregnant, and to children under the age of 3. The term “trace amounts” is defined by this law as 0.625 micrograms of mercury per 0.25 mL dose of influenza vaccine for children under 3, or 0.5 micrograms per 0.5 mL dose of all other vaccines for children under 3 and pregnant women. Because thimerosal (and thus, mercury) exists only in multi-dose vials of the influenza vaccines (both seasonal and novel H1N1), this law really only applies to these vaccines. The mercury concentration of the influenza vaccines is 25 micrograms per 0.5 mL, which therefore makes their use illegal. Unfortunately, the only form of the H1N1 vaccine initially distributed, and that could be used for young children and pregnant women, was the thimerosal-containing form. The thimerosal-free vaccine was the last to ship, and in low supply, and the nasal spray is a live-virus vaccine, not approved for use in pregnancy or children under 2. That meant, without a waiver of the thimerosal ban, these groups could not be vaccinated.
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Posted in: Politics and Regulation, Public Health, Science and Medicine, Vaccines

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Early Intervention for Autism

Many parents of children with autism have expressed to me their dismay that the anti-vaccine lobby is sucking all the oxygen out of the room for autism awareness. They feel that just being a parent of a child with autism makes others assume that they are anti-vaccine. They also worry that resources and attention are being diverted from promising legitimate research because of all the attention being paid to the failed vaccine hypothesis.

So it is good to occasionally focus on mainstream autism research to show that progress is being made, despite the unfortunate anti-vaccine sideshow.

A recent study published in the latest issue of Pediatrics shows that early intervention in toddlers with autism can have significant benefits. The study is a randomized controlled trial of  the Early Start Denver Model compared to conventional treatment in 18-30 month old children with a diagnosis of autism spectrum disorder (ASD). The study is a reasonable size for this kind of intervention – 48 children were randomized – and this is sufficiently powered to get statistical significance. But it should be noted this is still a smallish study and replication to confirm the results is welcome.

Another potential weakness is that the control group was “referral to community providers for intervention commonly available in the community.” Therefore the control group was not standardized and it’s possible this group was sub-optimally treated. Further, while the groups were randomized they were not blinded.

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Posted in: Neuroscience/Mental Health

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