News reports sometimes give questionable medical advice. Here are some big mistakes to watch out for in health news and what to pay attention to instead.
Relying on weak evidence
When a news report says, “Studies show . . .,” you should ask, “What kind of studies?” Some types of studies provide evidence strong enough to change medical practices, but others cannot by themselves guide reasonable decisions about your health. Look for the following problems:
Citing observational, not experimental, studies. News stories frequently feature observational studies, in which scientists gather information about various groups of people and look for patterns. Observational studies can show a statistical link between two factors but do not always account for other important factors. For example, a study that shows a relationship between more education and a longer lifespan might not account for the effects of income on both. Results of this kind can signal a need for more research but cannot prove that one thing causes another.
Instead, look for experimental studies, in which scientists recruit participants, give some of them an intervention—anything from medication or surgery to a change in diet—and then see how that intervention affects certain outcomes.
In particular, pay attention to news that cites randomized controlled clinical trials. In these studies, volunteer patients with similar characteristics are randomly divided into a group that receives an experimental treatment and a group that receives the current standard treatment or, if no standard treatment exists, a placebo. The strongest experimental evidence comes from systematic reviews and meta-analyses, which draw conclusions from the combined results of multiple clinical trials.
Citing preclinical, not clinical, studies. New drugs are tested in cells outside the body and then in animals such as mice before they are tested in humans, and these studies are too preliminary to directly affect patients. It’s interesting to hear that cancer cells die when treated with a new drug in a laboratory, but much more research is needed to show that the drug has the same effect inside the human body. Keep in mind that most drugs that seem to work in laboratory or animal studies ultimately don’t work in humans.
Citing anecdotes. The experiences of one patient or one doctor, or the experiences of a handful of patients and a handful of doctors, do not add up to conclusive evidence.
Exaggerating benefits and minimizing harms
A health news report needs to get specific when reporting how much an intervention affects an outcome. If you hear that yoga causes weight loss, ask how much weight and how much yoga; the effect could be negligible. Relative measures like “4 times more” or “3 times less” often conceal the true size of an effect. If you hear that coffee “halves” the risk of a particular type of cancer, find out what that risk is to begin with. If the original risk is very small—say, a risk of 0.5% over a lifetime—then halving that risk wouldn’t make much of a difference.
Also, the intervention’s possible side effects, along with their likelihood and severity, should always be mentioned; but some news reports skip this discussion. If the side effects of an intervention are not yet known, then that uncertainty should be frankly acknowledged.
Ignoring the options you already have
A new drug or procedure isn’t always better than the treatments that are already used for the same purpose. A report introducing an intervention should compare that intervention with current standard approaches. The option of simply not receiving the new intervention should be considered, too; for example, a condition that could be treated with a new surgical procedure could instead be managed through watchful waiting.
Ignoring availability or cost
Many reports about new interventions fail to talk about access. New treatments and tests that have not completed the clinical trials required for government approval can be given only to patients who are selected to participate in those trials. Such trials may take months or years to complete and may take place at only a few hospitals. Also, a complex procedure can take time to become widely used and may be available only through specially trained doctors.
In addition, interventions that have reached the public market may be widely available but not affordable. Insurance policies may not cover a new treatment or test, or the copay may be prohibitively high.
Reliable sources of health information
The common mistakes discussed in this article and the characteristics of good health news stories are described at www.healthnewsreview.org. For clearly written summaries of clinical effectiveness research, visit PubMed Health. Your doctor is also a reliable source of health information; talk to him or her before making health decisions based on news reports.
— S. Bronson
For more information, ask your physician or call askMDAnderson at 877-632-6789.
OncoLog, April 2015, Volume 60, Issue 4