A few days ago I wrote about a study that suggested that people who’d had bariatric surgery were at much higher risk of liver poisoning from acetaminophen than everyone else. I learned about the study from an article by Erin Allday in the San Francisco Chronicle. The article included this:
At this time, there is no reason for bariatric surgery patients to be alarmed, and they should continue using acetaminophen if that’s their preferred pain medication or their doctor has prescribed it.
This was nonsense. The evidence for a correlation between bariatric surgery and risk of acetaminophen poisoning was very strong. Liver poisoning is very serious. Anyone who’s had bariatric surgery should reduce their acetaminophen intake.
Who had told Allday this nonsense? The article attributed it to “the researchers” and “weight-loss surgeons”. I wrote Allday to ask.
She replied that everyone she’d spoken to for the article had told her that people with bariatric surgery shouldn’t be alarmed. She did not understand why I considered the statement (“no need for alarm”) puzzling. I replied:
The statement is puzzling because it is absurd. The evidence that acetaminophen is linked to liver damage in people with bariatric surgery is very strong. Perhaps the people you spoke to didn’t understand that. The size of the sample (“small”) is irrelevant. Statisticians have worked hard to be able to measure the strength of the evidence independent of sample size. In this case, their work reveals that the evidence is very strong.
If the experts you spoke to (a) didn’t understand statistics and (b) were being cautious, that would be forgivable. That’s not the case here. They (a) don’t understand statistics and (b) are being reckless. With other people’s health. It’s fascinating, and very disturbing, that all the experts you spoke to were like this.
I have no reason to think that the people Allday talked to were more ignorant than typical doctors. I expect researchers to be better at statistics than average doctors. One possible explanation of what Allday was told is that most doctors, given a test of basic statistical concepts, would flunk. Not only do they fail to understand statistics, they don’t understand that they don’t understand. Another possible explanation is that most doctors have a strong “doctors do everything right” bias, even when it endangers patients. Either way, bad news.