Good Placebos Gone Bad

Research Blogging / by Dave Munger /

Placebos are supposed to be inert controls, designed to prove a drug’s efficacy. Consequently, placebo composition is rarely documented in drug trials. Is this dangerous?

Credit: Flickr user Brooks Elliott

Placebo-controlled clinical trials are the gold standard of medical research. When doctors and other researchers want to know if a potential new drug is actually effective in treating disease, they design a controlled clinical trial comparing the drug to an ostensibly inert placebo. As I wrote last year, it’s critical to compare the drug to placebo, because otherwise it’s impossible to know whether the patients would have gotten better (or worse) anyways. Patients who believe their illness is being treated will often improve faster than those who are not confident that the treatment (or lack thereof) is actually helping. This is the placebo effect, and it’s a cornerstone of modern medicine. True placebos don’t have any power to treat disease; they just allow us to compare a proposed treatment to a neutral alternative.

But what if the placebo itself isn’t actually neutral? What if, for example, patients were allergic to some ingredient in a placebo? Might researchers be led into believing that the proposed treatment is more effective than it really is, since the placebo they’re comparing it to actually harms some patients?

You might argue that if this was the case, it would be a simple matter to take a look at the contents of placebos in a field of research and assess their potential side effects. Unfortunately, last week, UK medical writer Helen Jaques examined a recently published report suggesting that investigating the composition of placebos would not be a simple matter. A team led by Beatrice Golumb reviewed 176 clinical trials published in four highly-regarded medical journals in 2008 and 2009 and found that surprisingly few reports disclosed the contents of placebos used in the research. Only 23 percent of the trials gave full reports of the makeup of the placebos they used, and even counting partial reports, the number only increased to 32 percent. Studies involving pills (as opposed to shots or other treatments) disclosed even less: Just 9.3 percent of trials of pills gave full descriptions of the placebos used. The investigative report was published in Annals of Internal Medicine.

The report led one enthusiastic commentator, NaturalNews.com editor Mike Adams, to proclaim that the results of “thousands of clinical trials” must now be thrown out as invalid. Really?

Not so fast, the cancer surgeon and medical researcher who blogs as “Orac” responded last week. Orac points out that while the lack of placebo reporting is a concern that should be addressed, it doesn’t mean that placebos were never documented. While ideally the placebo’s composition should be reported in a formal research report, clinical researchers do document these things in lab notebooks, and are required to report placebos when submitting potential studies to ethics review boards. Any study that might be questionable could be verified after the fact.

Orac also wondered how frequent actual problems with placebos are in the real world. As one example, Golumb’s team identified lactose as a potential problem in placebos for cancer treatment, given that cancer patients in some cases tend to have higher-than-average levels of lactose intolerance. Orac looked up the references cited by the researchers and found no evidence that lactose in placebos resulted in any problems in the actual group of patients in the study in question.

That said, Orac concedes that there are potential problems with undocumented placebos, just not problems on the calamitous scale suggested by Adams. As Orac points out, Adams’ post is rife with errors, such as mistaking the .05 p value required for statistical significance for a drug “5% better” than a placebo (I should add that Adams also misquotes Shakespeare—which is almost as big a sin for former English majors like me). Adams claims that the problem with placebo documentation is a conspiracy on the part of pharmaceutical companies in order to market ineffective medication, but the study authors don’t even hint at this possibility. As Jaques points out, even Golumb says that the problem is not due to “willful manipulation,” it’s just an issue that needs to be addressed.

None of this is to say that pharmaceutical companies and the independent researchers they fund should be given a free pass. As the neuroscientist who blogs as “Neuroskeptic” wrote in September, drug companies have huge financial incentives to overstate the effectiveness of their products. In an article published in Clinical Pharmacology and Therapeutics, researchers proposed filtering out results of clinical trials from clinics where the placebo effect was unusually strong. As a result, the drug being tested would appear more effective—but in the process, Neuroskeptic argues, the clinical trial would no longer be truly random. This type of “cherry-picking” isn’t good science, and researchers shouldn’t be allowed to get away with it.


Dave Munger is editor of ResearchBlogging.org, where you can find thousands of blog posts on this and myriad other topics. Each week, he writes about recent posts on peer-reviewed research from across the blogosphere. See previous Research Blogging columns »

 

Originally published November 3, 2010

Tags medicine proof public perception

Share this Stumbleupon Reddit Email + More

Now on SEEDMAGAZINE.COM

  • Ideas

    I Tried Almost Everything Else

    John Rinn, snowboarder, skateboarder, and “genomic origamist,” on why we should dumpster-dive in our genomes and the inspiration of a middle-distance runner.

  • Ideas

    Going, Going, Gone

    The second most common element in the universe is increasingly rare on Earth—except, for now, in America.

  • Ideas

    Earth-like Planets Aren’t Rare

    Renowned planetary scientist James Kasting on the odds of finding another Earth-like planet and the power of science fiction.

The Seed Salon

Video: conversations with leading scientists and thinkers on fundamental issues and ideas at the edge of science and culture.

Are We Beyond the Two Cultures?

Video: Seed revisits the questions C.P. Snow raised about science and the humanities 50 years by asking six great thinkers, Where are we now?

Saved by Science

Audio slideshow: Justine Cooper's large-format photographs of the collections behind the walls of the American Museum of Natural History.

The Universe in 2009

In 2009, we are celebrating curiosity and creativity with a dynamic look at the very best ideas that give us reason for optimism.

Revolutionary Minds
The Interpreters

In this installment of Revolutionary Minds, five people who use the new tools of science to educate, illuminate, and engage.

The Seed Design Series

Leading scientists, designers, and architects on ideas like the personal genome, brain visualization, generative architecture, and collective design.

The Seed State of Science

Seed examines the radical changes within science itself by assessing the evolving role of scientists and the shifting dimensions of scientific practice.

A Place for Science

On the trail of the haunts, homes, and posts of knowledge, from the laboratory to the field.

Portfolio

Witness the science. Stunning photographic portfolios from the pages of Seed magazine.

SEEDMAGAZINE.COM by Seed Media Group. ©2005-2012 Seed Media Group LLC. All Rights Reserved.

Sites by Seed Media Group: Seed Media Group | ScienceBlogs | Research Blogging | SEEDMAGAZINE.COM