A study published last month in JAMA Internal Medicine found that high-risk Medicare patients with heart failure or cardiac arrest admitted to teaching hospitals had significantly better outcomes during periods when national cardiology meetings were held.

For the years 2002 to 2011, 30-day mortality rates in teaching hospitals for heart failure were 17.5% during national meetings vs. 24.8% (p <0.001) in non-meeting times and cardiac arrest mortality rates were 59.1% and 69.4%, respectively, (p = 0.01).

Another interesting finding was that high-risk patients with acute myocardial infarctions were significantly less likely to undergo percutaneous coronary intervention during meeting times, 20.8% vs. 28.2% (p = 0.02).

Of course, critics of the study pointed out its retrospective design, its small numbers in some categories, and good old “association is not causation,” but it certainly rattled a few cages.

What most of the naysayers missed was that the outcome differences only occurred in high-risk patients in teaching hospitals.

From the paper: “Adjusted mortality also generally did not differ between meeting and nonmeeting dates for low- or high-risk patients in nonteaching hospitals. For example, adjusted mortality for high-risk patients with heart failure during meeting and nonmeeting dates was 24.6% (95% CI, 23.2%-26.0%) and 24.5% (95% CI, 24.0%-25.1%), respectively (P = .91).”

In an accompanying editorial, Dr. Rita F. Redberg wrote, “It is reassuring that patient outcomes do not suffer while many cardiologists are away.” That’s what I call putting a positive spin on as negative a study as one could imagine. She also said, “One possibility is that more interventions in high-risk patients with heart failure and cardiac arrest leads [sic] to higher mortality.”

On the Incidental Economist blog, Dr. Aaron Carroll also wondered about the results saying, “Maybe the best cardiologists were the ones who stayed home. Maybe with fewer cardiologists available, fewer invasive procedures get done, and that leads to better outcomes. Maybe they tell more low-risk patients to wait when fewer cardiologists are available, which gets the higher risk patients more attention and better outcomes. Maybe it’s something else.”

However, the authors of the paper wrote that there was “no evidence that total cardiovascular hospitalization volume declined during meeting dates” and speculated that “rates of same day elective procedures and outpatient visits may have declined, which could have the same positive effect on patient outcomes.”

An article about the paper in the Dallas Morning News quoted Dr. Patrick O’Gara, president of the American College of Cardiology, who said “the study’s observational design makes it impossible to know if the national meetings had any effect on patients’ survival. He also noted that the number of heart doctors who attend the national meetings is a fraction of the nearly 30,000 cardiologists nationwide.”

There were 27,076 cardiologists in the United States in 2013. The paper noted that 13,000 to 19,000 cardiologists attended the national meeting of the American Heart Association during the years studied, and the American College of Cardiology website reported 20,000 attendees at its 2014 meeting. These might not all be cardiologists, and some could be from other countries. But it’s difficult to call this many attendees “a fraction” of the total number of cardiologists in the US.

I have yet to hear a convincing refutation of the papers’ conclusion which was, “One explanation for these findings is that the intensity of care provided during meeting dates is lower and that for high-risk patients with cardiovascular disease, the harms of this care may unexpectedly outweigh the benefits.”

Skeptical Scalpel is a retired surgeon and was a surgical department chairman and residency program director for many years. He is board-certified in general surgery and critical care and has re-certified in both several times. He blogs at SkepticalScalpel.blogspot.com and tweets as @SkepticScalpel.