A new test to help determine a more definitive diagnosis for people who suffer from gastrointestinal problems such as diarrhea and bloating would be a very good thing. Seeing as millions of people around the world suffer from uncomfortable and embarrassing symptoms that might be related to an irritable bowel, a better test to diagnose the condition could have far reaching implications. Unfortunately this story struck out on almost all counts — lacking detail on current ways to diagnose IBS, giving no sense of the magnitude of benefits or harms, and ultimately failing to deliver an adequate explanation of how patients would be better off if they receive a more definitive diagnosis of IBS. These shortcomings are similar to those of the news release that likely prompted the story, and which we also subjected to a systematic review.
Irritable bowel syndrome affects millions of Americans and often the diagnosis is difficult to pinpoint as there may be many and variable causes that produce gastrointestinal symptoms. A better diagnostic test may relieve anxiety, help direct quicker therapy, and avoid other diagnostic tests that may be invasive. It could also provide quicker relief to patients and help them avoid treatments wouldn’t work for them.
No mention of cost, and it’s not clear from the story if the tests are commercially available. Since there’s a consumer website devoted to the tests, we assume they can be purchased, but couldn’t find any cost information on the site. The story could have enlightened us.
A CBS News chief medical correspondent weighed in to say that a “positive test result is highly suggestive of IBS, [yet] only 44 percent of patients with IBS tested positive, meaning that many people who test negative could in fact still have the condition.” This is an important caveat, but any reporting of a new test should be able to discuss both the magnitude of benefit as well as the potential magnitude of false negatives AND false positives. Instead of describing a positive test result as “highly suggestive,” the story could have given us the actual numbers from the study.
No test is 100 percent accurate, and a false positive test can lead to additional diagnostic testing that can cause harm as well as unnecessary treatments. The story could have mentioned this.
The story refers to this test being useful for “IBS” in general which is not correct. There are many forms of IBS with various symptoms, and this is a test for patients with chronic diarrhea – or IBS with diarrhea as the primary component. The story is simply wrong to use the general term “IBS” to describe this subgroup of IBS patients. Many, perhaps most, patients with IBS stand to gain nothing from the use of this test because they don’t have the specific symptoms that comprise this type of IBS.
The story also provides no sense of the limitations of the study used to validate this test and which are clearly described in the original paper. One of the important caveats mentioned in the journal paper is that 10-15% of inflammatory bowel disease (esp Crohn’s disease) patients also have IBS, so it’s not clear what the test means for these people. Second, the story doesn’t describe that while the IBS population is large, there were only 43 control patients. It is hard to know how specific the test is without testing in more controls.
The story says IBS affects 25 million to 45 million people in the U.S. While this may be true, the test we’re talking about isn’t a test for IBS in general — it’s a test for those with the diarrhea predominant version. It’s not clear how many people this amounts to, but according to this study, less than half of the people with IBS meet the criteria for the diarrhea-predominant version. The story exaggerates the potential impact of the test in a way that promotes a commercial interest, so we’ll flag it for disease mongering.
The quoted CBS news correspondent casts a sufficiently critical view of the test, yet it is hard to say if he is conflicted or not, seeing as he works for the same news outlet the news story has appeared in. It would have been relatively easy to discuss the tests with an outside expert unconnected to the test manufacturer or the news network.
In addition, Dr. Pimental is quoted in the story as “the developer of the tests.” Most people will probably understand that he has a financial interest, but this could have been made more clear by saying so — disclosing that he’s a paid consultant of the companies developing the tests commercially.
Even a mention of an alternative (such as how IBS is currently diagnosed) would have merited a satisfactory, but there is no mention of alternatives.
We don’t know if the tests are available, and we don’t learn anything about how far away from commercialization they might be.
The article says the tests (and maybe even the hypothesis underlying the test) are new.
The article also says this is the first time evidence has shown that IBS has an organic basis.
The description of “two simple blood tests” is suspiciously similar to copy from a news release issued a few days before the story was posted. And certainly the narrative of the story mirrors what we found in our review of that news release. But since the story does include at least one comment that puts a brake on some of the claims made by the manufacturer, we’ll give the benefit of the doubt here and award a Satisfactory.