Studying the Studies
June 14, 2007
More and more, patients are bringing in stacks of articles they have printed from the Internet. Some of my physician colleagues get irritated over this, since they do not have time to go over all these studies. I have actually found it to be an opportunity to discuss with patients how to interpret what they learn online. The old adage, "just 'cause it is printed, it doesn't mean it's true", also applies to the Internet: just cause you can Google it, doesn't mean that the studies are good.
I always encourage patients to search the Internet and read studies, but I also tell them to bring them in to discuss. In medical research, we refer to the "hierarchy of evidence." Some types of studies are better than others. You want to spend more time reading the articles that involve the best type of studies.
So what do you look for? Here’s a general overview:
The best type of study is a randomized clinical trial. Here, we test a drug or treatment by comparing two groups: one is called the experimental group and the other is the control group (this one is simply observed). Usually, we like them to be double-blinded, meaning neither the doctor nor the patients knows whether they are receiving the drug or placebo.
A cohort study follows a group of people over time to determine which persons develop a disease. These studies often give us information about various prevention strategies. Cohort studies are better if they are prospective (outcome has not occurred yet) rather than retrospective (outcome has already occurred).
Case-control studies are typically retrospective: patients who have a disease are compared with those who do not. We then study differences in these patients to determine causes of the disease.
A meta-anaylsis is a review of studies that collects and pools all the results. These types of studies have become much more common. The key is to look at the studies that were combined; remember "garbage in, garbage out."
If you're reading the actual study, look in the "Methods Section" and keep in mind the hierarchy of evidence. No one expects you to be able to understand everything on a medical study, but do a little bit of "research on the research" and you'll become a more informed patient.
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