Over the long weekend I caught up on some reading. One article* stands out. It’s on informed consent, and the stunning disconnect between physicians’ and patients’ understanding of a procedure’s value.

The study, published in the Sept 7 Annals of Internal Medicine, used survey methods to evaluate 153 cardiology patients’ understanding of the potential benefit of percutaneous coronary intervention (PCI, or angioplasty). The investigators, at Baystate Medical Center in Massachusetts, compared patients’ responses to those of cardiologists who obtained consent and who performed the procedure. As outlined in the article’s introduction, PCI reduces heart attacks in patients with acute coronary syndrome – a more unstable situation than is chronic stable angina, in which case PCI relieves pain and improves quality of life but has no benefit in terms of recurrent myocardial infarction (MI) or survival.

The main result was that, after discussing the procedure with a cardiologist and signing the form, 88% of the patients, who almost all had chronic stable angina, believed that PCI would reduce their personal risk for having a heart attack. Only 17% of the cardiologists, who completed surveys about these particular patients and the potential benefit of PCI for patients facing similar scenarios, indicated that PCI would reduce the likelihood of MI.

This striking difference in patients’ and doctors’ perceptions is all the more significant because 96% of the patients “felt that they knew why they might undergo PCI, and more than half stated that they were actively involved in the decision-making.”

What we have, here, is a study of informed consent, set up in a way that the doctors knew the study was ongoing – because they and their patients were participating, all in one division of one hospital – and, presumably, spent if anything more time and not less than usual talking with patients and answering questions about the procedure. (Note: this particular point is an assumption on my part, supported by the reported fact that 83% of the patients reported that their questions had been answered.)

The central finding is a failure of communication between doctors and patients about the potential benefit of the procedure: 88% of the patients, who’d signed consent, thought that PCI would prevent heart attacks and only 17% of the cardiologists at the same medical center thought the same. This matters, first, because over a million people in the U.S. undergo angioplasty each year and, more broadly, because it represents an everyday outgrowth of the  phenomenon of therapeutic misconception – when patients think a procedure has a greater potential benefit than it does.

The concept of therapeutic misconception, as was initially defined narrowly in the context of clinical trials, applies to all areas of medicine. In cancer treatment it’s a big deal but, in my experience, under-addressed. A common misconception among breast cancer patients, for example, concerns the benefit of adjuvant chemotherapy, which generally reduces the odds of recurrence by about a third. So if you have a stage II tumor with good molecular features and the odds of recurrence are somewhere around 15%, that comes down to around 10% with the treatment, which does bear significant side effects and risks. Another fairly common misunderstanding in oncology is in the area of Phase I clinical trials, in which the drugs are tested for toxic effects in humans, and to see how much people can withstand, and not for therapeutic effect.

This topic is worthy of lots more discussion than I can afford here. I do recommend reading the full article, including the methods about how the survey was done, and the editorial* in the Annals, which accompanied the paper, which like so many other provocative and significant reports in the medical literature, didn’t get much attention in the lay press.

One point the editorial considers is that, perhaps, the PCI consent form used by the study authors and said to be at a 12th grade reading level, should instead be provided at an 8th grade level, as some institutions recommend and require. I’m not so sure about this, because I think a lot of medical ideas and decisions simply cannot be communicated at a lower level without loss of content, i.e. nuanced information.

I’m eager for readers’ views on this – how often is it that doctors effectively convey why a procedure should be done or a treatment be given, and what might be done to improve the process?

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