Weekend Reading

20Apr13

It’s been a staggering week, news-wise. As we all watched the events in Boston and Texas, here’s what you may have missed.

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It’s 2013. Enough With the “False Balance” on the MMR vaccine

15Apr13

It’s tempting to blame the re-emergence of measles in the United Kingdom squarely on Andrew Wakefield. After all, Wakefield’s 1998 paper in the Lancet (now retracted) attempted to link the measles, mumps, and rubella vaccine with autism. This research was later shown to be fraudulent. His actions was so heinous that he was eventually stripped of his medical license for unethical behavior, including research misconduct and undeclared conflicts of interest. But not before a long period of “false balance” in the UK media that repeatedly offered fringe, scientifically unsupported opinions that the MMR vaccine safety was in question. Why would the media do this? Controversy sells. The brave maverick physician standing up against the medical establishment – Big Pharma, even. But this was a narrative completely out of line with the facts. There has never been any serious scientific controversy about the MMR vaccine and autism – none. Carefully controlled studies, conducted after Wakefield’s initial paper, have failed to show any relationship. Yet the reporting didn’t reflect this, for years. False balance has the potential to be incredibly damaging. I’ve pointed out in the past that viewing anti-vaccine material for only five to ten minutes increased the perception of risk of vaccination, and decreased the perception of risk of omitting vaccines. It also lowers vaccination intentions. By changing perceptions of safety, the willingness to vaccination decreases. This is a common tactic of antivaccinationists – raising questions about safety and effectiveness. And it’s something the UK media continued for several years, until Wakefield was eventually investigated, discredited, and disgraced.

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Tags: andrew wakefield, MMR, vaccines

Weekend Reading

12Apr13

Vaccines Work

More posts are imminent…here’s what I’ve been reading.

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Cranberry: The Alt-Med Zombie

11Apr13

If there’s a characteristic that’s common among proponents of alternative medicine, it’s tenacity. The willingness to stick with an idea, no matter the evidence, must give one a certain clarity. The naturalistic fallacy is often the foundation. Natural is good, and anything synthetic is bad. In some cases, beliefs persist in spite of the evidence. How one deals with contradictory evidence is an effective tool to differentiate between medicine and alternative medicine – given sufficient convincing evidence, medicine changes its practices. The same can’t be said for alternative medicine, where few treatments are ever discarded. Otherwise practices like homeopathy, acupuncture, reiki, and chiropractic would have disappeared long ago. It’s also why disproven products continue to have occasional resurgences in interest. Cranberry is one. It has been touted as a treatment and a preventative for urinary tract infections for years. And it doesn’t seem to work – not well, and not reliably, if you look at all the trials. And that’s being generous, considering the poor quality of the evidence with its inherent biases. I know a dead parrot when I see one. Yet its advocates, mainly manufacturers (is there a Big Cran?) keep insisting it’s alive, supported by the occasional positive report that appears. With a new systematic review and meta-analysis that declares it’s effective, it’s time to update our review.

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Tags: cranberry, urinary tract infections

Weekend Reading

05Apr13

Winter won’t let go in Canada. Here are some articles and posts of interest to SBP’s readers:

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(Long) Weekend Reading

29Mar13

If you’re lucky to have a long weekend, enjoy. Here’s an extra dose of reading:

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Tags: gluten free diet, paleo diet, vaccines

What a suvey of placebo use really tells us

28Mar13

One of the key concepts essential to science-based medicine is the placebo: What it is, what it isn’t, and how it complicates our evaluation of the scientific evidence. One my earliest lessons after I started following the Science-Based Medicine blog was that I didn’t understand placebos well enough to even describe them correctly. Importantly, there is no single “placebo effect”. They are “placebo effects”, a range of variables that can include natural variation in the condition being studied, psychological factors and subjective effects reported by patients, as well as observer bias by researchers studying a condition. All of these, when evaluated in clinical trials, produce non-specific background noise that needs to be removed from the analysis. Consequently, we compare between the active treatment and the placebo to determine if there are an incremental benefits, to which we apply statistical tests to determine the likelihood that the differences between the intervention and the placebo groups are different from random chance. Removed from the observational nature of the clinical trial, we can’t expect the observed “placebo effects” to persist, as they’re partially a consequence of the trial itself. A more detailed review of placebos is a post in and of itself, so I’ll refer you to resources that describe why placebo effects are plural, that placebo effects are subjective rather than objective and there is no persuasive evidence to suggest that placebo effects offer any health benefits. What’s most important is the understanding that placebo effects are a measurement artifact, not a therapeutic effect.

Placebo effects are regular topics at this blog, because an understanding of placebo effects is essential to evaluating the evidence supporting (so-called) complementary and alternative medicine, or CAM. As better quality research increasingly confirms that the effects from CAM are largely, if not completely, attributable to placebo effects, we’ve seen the promoters of CAM shifting tactics. No longer able to honestly claim that CAM has therapeutic effects, “treatments” such as acupuncture or homeopathy are increasingly promoted as strategies that”harness the power of placebo” without all the pesky costs or side effects of real medical interventions. But this is simply special pleading from purveyors and promoters. Unable to wish away the well-conducted trials that show them to be indistinguishable from placebos, they instead are spinning placebo effects as meaningful and worthy of pursuit – ideally with your favourite CAM therapy. Again, I’ll refer you to posts by David Gorski and Steven Novella who offer a more detailed description of how negative results can be spun to look positive. Because CAM’s effects are indistinguishable from placebo, we should not invest time and resources into pursuing them – we should instead focus on finding treatments that are demonstrably superior to placebo.

But what if physicians are already using placebos widely in practice? Setting aside the ethical issues for now, widespread placebo usage might suggest that physicians believe that placebos are effective treatments. And that’s the impression you may have had if you skimmed the medical headlines last week:

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Tags: cam, clinical trials, placebo, placebo effects