Misconceptions about drug side effects and clinical trial results

“I don’t want to take Avandia because it will give me a heart attack!”

“My dentist told me that my gums are bleeding because of Fosamax, so I stopped it!”

“Vytorin is going to give me a stroke!”

These are but a few of the comments I have heard from my patients. No one has asked to be taken off of Lantus because of concerns about risks for cancer, but I will not be surprised when they do.

Interpreting results of a clinical trial can be challenging and confusing for physicians. Thus, I am not surprised when results are misinterpreted by patients. The lay media thrives on reporting negative or unexpected results. Let’s face it: Fear and anxiety sell. In contrast, study data that confirm what we have suspected or disprove previous negative press are boring. Too often, such studies are put on the back page or not reported at all.

To give you an example, imagine a study comparing the effects of Drug A to placebo. In this study, it was found that the risk of a side effect was increased from 0.001% in the placebo group to 0.002% in the Drug A group. Rather than stating that the absolute risk increased by only 0.001%, the media instead reports, “Drug A doubles risk!” That makes the results sound much worse than they are.

Whether a 0.001% increase in absolute risk is important depends on how serious the side effect. It also depends on the risks of the condition being treated as well as the risks of other therapies. That discussion is too complicated for a brief sound byte.

I am not suggesting that negative outcomes of therapy or side effects should be ignored — absolutely not. Every therapeutic decision, including a decision to do nothing, has both positive and negative possible consequences. As clinicians, we must decide daily whether a treatment option is worth it in terms of benefits, cost and potential side effects.

I try to explain this as best I can to my patients. Physicians often cringe when patients show up with a copy of the package insert with every side effect of concern highlighted. However, engaging in an open discussion about the merits and disadvantages of various treatment options is an important aspect of medicine. Our duty is to inform and advocate. If one treatment option is much better than others, I will tell my patients so and why. However, in the end it is still the patient’s decision, and we must not forget that.

Unfortunately, the constraints of medical practice limit how much time we can devote to this discussion. Patients are frequently handed a prescription without full explanation of risks/benefits. They seek information and do not always get it from reliable or fully informed sources. Nevertheless, time spent answering questions goes a long way in ensuring compliance with therapy. It is also the foundation of every successful doctor-patient relationship.