Recently in preparing a talk I was giving in Bologna I found a copy of a talk I’d given to WONCA, the world meeting of general practitioners, back in the era before Powerpoint existed, and it contained information on a study that has stuck in my head for 20 years, but which I couldn’t find. (And after 20 minutes of searching I still can’t find the study, but perhaps you can.) It’s a study that suggests that patients are regularly misled, even abused, because they are not given full information.

The study was done in California (which suggests the future to some and flakiness to others), and 100 patients aged 50-75 from California were asked about their preferences for different methods of screening for colorectal cancer; 93 of them had been screened previously. The methods were faecal occult blood testing, flexible sigmoidoscopy, colonoscopy, and a barium enema, and the participants were given detailed, evidence based information on each; they were also given the same information for no screening.

The information included a description of the test, the preparation required, the need for sedation, the time required, time missed from work, how often it would be repeated, the likely discomfort, the lifetime probability of developing colon cancer, the chances of dying of it, the percentage of cancers prevented, the risk of perforation of the colon, and the cost.

There were, as you would expect, considerable differences among the methods: for example, colonoscopy, which is time consuming, uncomfortable, and expensive compared with faecal occult blood testing, would reduce the lifetime risk of dying of colon cancer from 1.9%  with faecal occult blood testing to 0.6%. (The reliability of these data must be open to doubt, and participants were not given confidence intervals. But the accuracy of the data doesn’t matter for this study.)

The participants were then asked three questions: Which option would you chose? How likely would you be to undergo each of these? Would you have this test if recommended by the physician?

There was a very wide scatter in which test people would chose: 4% would not be screened; 31% would chose faecal occult blood testing;  38% colonoscopy; 14% barium enema; and 13% flexible sigmoidoscopy. There was also variation in the likelihood of people undergoing each test, but almost all participants would have each test if it was recommended by their doctor: faecal occult blood screening (96%), sigmoidoscopy (82%), barium enema (92%), and colonoscopy (86%).
In other words—even in California—most patients would allow the doctor’s advice to override their own preferences. Steve Woolf, a professor of family practice, put it thus in an accompanying editorial:

“Suppose these same 100 patients had not received this information and were instead cared for by a physician who routinely performs flexible sigmoidoscopy because he considers it the best test. According to these data, fully 87% of the patients would undergo a procedure other than the one they would prefer if properly informed.”

Is this patient abuse? I think it is, but, of course, it happens all day everyday everywhere—because doctors have neither the knowledge nor the time to fully inform patients. We must surely eventually move to computer aided informed consent. Some have been doing this for years. Why can’t it be routine? Without it patient choice is empty rhetoric.

Competing interest: RS is the chair of Patients Know Best. He is not paid but has equity in the company.

Richard Smith was the editor of the BMJ until 2004 and is director of the United Health Group’s chronic disease initiative.