A comparison of two diagnostic tests — traditional stress tests and newer heart CTA (computed tomography angiogram) scans — among more than 10,000 heart patients found no difference in those patients’ incidence of subsequent heart attacks and related complications, suggesting that the two types of testing work equally well. Further, that incidence—3 percent—was so low that researchers suggested that “watchful waiting” may be a viable alternative to such diagnostic tests. Missing from this story is any reflection on cost; other researchers have found that the CT scan is associated with much higher health care spending rates. We also thought the story could have done without a misleading closing anecdote that badly undercuts the main message of the story.
The arrival of new diagnostic procedures always seems to promise more effective treatment. But effectiveness is an empirical question, and this study’s findings suggest that the familiar stress tests work just as well as heart CT scans. That result could have a substantial impact on treatment costs.
Costs do not surface in this story. Since one would assume that a CT scan would be considerably more expensive than traditional stress tests, this seems to be an important omission. A bit of digging would have made apparent another type of cost between the two kinds of tests: A 2011 observational comparison of these two modalities among Medicare patients (published in the Journal of the American Medical Association) found that heart-related health-care spending was substantially higher among patients who received coronary CT angiography compared with traditional stress testing.
This is an example of a story thrown off course by a single misleading anecdote.
Discussion of benefits is quite reasonable for 90% of the story, and we noted that the report offers specific information on the incidence of heart attacks or complications—3%—in the course of making the point that the incidence does not differ between patients undergoing stress tests versus CTA. The story also notes that CTAs “result in fewer instances of patients with suspected heart issues undergoing unneeded catheterization procedures.” That’s all very well and good.
But at the very end, we learn of one patient who underwent CTA even though his stress test was normal, and whose life was apparently saved as a result. The man convinces his two brothers to get CTAs, which apparently reveal blockages that they were unaware of. “Just because I had a CTA, that had a domino effect to my brothers getting it, and it very well saved all three of our lives,” the man says.
Unless this man can predict the future, how could he possibly know that getting a CTA saved his life or those of his brothers? These men may have had blockages, but it’s not at all clear that these blockages would have resulted in fatal heart attacks. In fact, a major concern with CTA is that it may reveal blockages that would never cause a serious problem, leading to unnecessary procedures. The point of the study is that there was no difference at all in the incidence of serious cardiac complications between those who undergo stress tests and those who get CTA.
Unfortunately, that careful science-based message is badly undercut by the story’s failure to push back against this anecdotal crystal ball-gazing. It’s likely that any readers who make it to the end of this story will conclude that it’s best to get a CTA, just in case.
Potential drawbacks of these interventions are not discussed. The press release describing this study did note potential harms of the stress tests: they were associated with more catheterizations, and nuclear stress tests were associated higher levels of radiation exposure compared with CTA. But the story did not pick up on that information. (There was also no mention of the fact, either in the story or press release, that standard exercise electrocardiography involves no radiation exposure, and would presumably be the lowest-risk option as far as radiation is concerned.) As noted above, the only hint of possible harm that occurs is an end-of-story anecdote about an individual whose stress tests failed to signal the presence of blocked arteries. The inference here is that stress tests can miss diagnostic signals that CTA will find. Oddly, the anecdote seems incongruent with the main message of the story.
The article offers reasonable detail about the study methods, including the large sample size (more than 10,000 heart patients) and patients’ random placement into one of the two stress test conditions. It fails to explain that the study monitored incidence of problems for only two years after tests, information that was provided in the press release.
This story had competing impulses. On the one hand, the story mediates against disease-mongering by indicating that the low incidence of later heart problems among the participants suggests the value of “watchful waiting” rather than treatment. On the other, the anecdotal story at the end of the text heads in the opposite direction, suggesting that stress tests miss vital diagnostic information. But we don’t think anything in the story rises to the level of disease mongering.
Neither the story nor the original press release indicates the presence of conflicts of interest. That may be reasonable, as the research was funded by the National Heart, Lung, and Blood Institute of NIH. The one outside scientist quoted in the story is clearly described as independent of the study.
The whole point of the study was to compare a newer and an older approach to diagnosing heart problems.
Although the story does not make information about availability explicit, it is reasonably clear from the story that both types of diagnostic tests are currently available.
The story heralds this comparison as the first of its kind in terms of examining clinical outcomes of folks getting these diagnostic exams. It appears that is true.
The story seems to have gone beyond the press release by interviewing the lead study author, gathering reactions from a researcher outside the project, and adding an anecdotal story to the text. That anecdote, by the way, makes the main point of the story more murky rather than more clear.
Systematic, Criteria-Driven
The tale of two “negative” studies. Or, how spin is applied to make research findings look more impressive. A must read. https://johnmandrola.substack.com/p/the-tale-of-two-negative-studies
The @nytimes chose to interview one of the editors of the @AnnalsofIM (publisher of this paper) who "gushed with extraordinary glee: It’s huge! There are very few things that reduce your mortality by 30%."
Turns out coffee is not one of those few things despite all that glee. https://twitter.com/garyschwitzer/status/1533202075928215558
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