Null but not void: Why health journalists need to stop ignoring negative studies

Mary Chris Jaklevic is a freelance health reporter who’s written for many newspapers and magazines and has sat on the board of the Association of Health Care Journalists. She tweets as @mcjaklevic.

Does using a statin improve your odds of surviving cancer? The typical news consumer might be excused for thinking the answer is yes, despite evidence to the contrary.

That’s because news coverage of this issue has focused on positive findings from weak observational studies that suggest statins may have cancer-fighting properties. Far less media attention has been devoted to rigorous trials that show statins don’t actually improve cancer outcomes.

Can statins help treat cancer? News coverage has focused on preliminary, positive studies and neglected stronger, negative evidence.

This impulse to cover positive findings — no matter how shaky — and neglect stronger null findings pervades medical journalism. It’s particularly obvious with statins, as pharmaceutical companies push for new uses of these old drugs in order to expand their market.

Take a randomized, double-blind, placebo-controlled trial published last week that found a statin offers no benefit over chemotherapy alone for patients with small cell lung cancer, a fast-growing disease with a low survival rate that accounts for about 15 percent of lung cancers in the U.S. This sobering reality check garnered almost no mainstream news coverage. A story did run in the British daily The Times. You can also read about it at MedPage Today, a news service for clinicians.

Upbeat findings dominate mainstream coverage

By contrast, there’s been copious coverage of unreliable observational studies that link statins to benefits such as delayed recurrence or longer survival when used with other therapies against cancer. A few examples: has evaluated eight stories that reported on positive links between statins and better cancer outcomes, most recently HealthDay’s Could Statins Help Fight Cancer? and The Guardian’s Statins ‘could be valuable addition to breast cancer treatment.’ Publisher Gary Schwitzer also blogged in 2012 about uneven coverage of a Danish study showing a statistical association between statin use and fewer cancer deaths and in 2013 about speculative CBS coverage that hyped statins as a “new wonder drug.”

You have to go back 11 years — to 2006 — to find a review of a story reporting no link, the Associated Press’s Studies: Statins don’t lower cancer risk.

These stories often acknowledge the limitations of observational studies — which are quick and economical but subject to bias — as well as the need for confirmation with more prolonged and costly controlled trials. But the reality is, readers don’t always get that far into a story. And the fact that tentative findings get covered bestows a measure of credibility.

Positive findings meet journalistic needs

Several factors seem to be at work. Positive findings that tend to dominate early research make alluring stories, particularly when it comes to potentially curing a horrible disease. Headlines announcing something doesn’t offer a benefit won’t grab readers, unless they involve doing burpees or cutting back on red meat.

Plus, initial findings fit the journalistic mission to be timely, even if they’re dubious.

Also, negative findings may be less visible to journalists because they have a harder time getting published in journals, said Estelle Dumas-Mallet, a researcher at the University of Bordeaux, via email. She co-authored a recent study examining 1,561 newspaper articles on medical studies examining associations between risk factors and disease. News releases also influence coverage, she noted.

The study found newspapers prefer to cover initial studies over subsequent research investigating the same question. Among 53 initial studies covered by newspapers, all showed a positive association. Two-thirds of those initial findings were refuted by subsequent research, but journalists seldom wrote about it.

Notably, the drop-off in subsequent coverage was less striking for research that involved lifestyle factors, things within a person’s control such as diet and smoking, which tend to draw a lot of clicks. The fact that lifestyle studies are often reported even when they’re negative “supports the view that the first journalists’ aim is to attract readers’ attention,” the researchers wrote.

Science self-corrects; journalism does not

The fact that many initial findings are overturned isn’t necessarily a problem for science, which is a “cumulative process that reduces uncertainty by combining uncertain initial findings with validation by subsequent studies,” according to the researchers.

But that self-correction doesn’t always occur in journalism, skewing perceptions and potentially setting up unrealistic expectations for patients. For example, newspapers continued to cite a 2003 study linking genetics to the risk of stress-induced depression well after the finding was refuted by a meta-analysis, which “deflected public attention away from the considerable impact of social inequalities upon health,” the researchers wrote.

In a column for STAT, Retraction Watch co-founders Ivan Oransky and Adam Marcus point to “unfortunate consequences” when the media seize on stories about flawed science, such as the discredited link between autism and vaccines.

Oransky, a distinguished writer In residence at New York University’s Carter Journalism Institute and an editor at-large for MedPage Today, said via email that “people should be able to make health care decisions based on the best evidence possible. If someone’s doctor is recommending a particular treatment, that decision should be based on the evidence for that treatment, including high-quality guidelines, if possible, not some hyped study that promises the treatment is also going to prevent cancer.”

It’s the strength of the data that matters

Covering breaking medical news for clinicians, MedPage Today has a distinct outlook. “In our world a negative or null study can often be seen as ‘good’ a story as a positive result,” Editor-in-Chief Peggy Peck wrote in an email. “I think that should be the case regardless of the audience, but since our target audience comprises healthcare professionals, there is no question that the findings matter – especially findings that involve therapies that are readily available like statins.”

One example she gives is when a drug enters the market and quickly dominates, but then isn’t supported by evidence in a head-to-head trial. That was the case in 2008 when Vytorin, a cholesterol-lowering combination of the drug ezetimibe and a statin, was found not to slow progression of atherosclerotic plaque compared with a statin alone. By then it had been prescribed to millions, and doctors immediately backed off writing scripts.

Evidence that statins aren’t effective against cancer may be getting scant coverage, but it’s bound to alter patient care. Citing four other published trials with negative results, researchers in the most recent study urged that ongoing trials on statin therapy for cancer should “stop early if there is sufficient evidence for futility, thus saving resources.”

As Peck wrote: “Bottom line: positive or negative, results count.”

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