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Tag: Medical studies

How Bad Is Azithromycin’s Cardiovascular Risk?

The paper from the New England Journal of Medicine that reports azithromycin might cause cardiovascular death is not new to electrophysiologists tasked with deciding antibiotic choices in patients with Long QT syndrome or in those who take other antiarrhythmic drugs.   Heck, even the useful Arizona CERT QTDrugs.org website could have told us that.

What was far scarier to me, though, was how the authors of this week’s paper reached their estimates of the magnitude of azithromycin’s cardiovascular risk.

Welcome to the underworld of Big Data Medicine.

Careful review of the Methods section of this paper reveals that “persons enrolled in the Tennessee Medicaid program” were the subjects, and that the data collected were “Computerized Medicaid data, which were linked to death certificates and to a state-wide hospital discharge database” and “Medicaid pharmacy files.”   Anyone with azithromycin prescribed from 1992-2006 who had “not had a diagnosis of drug abuse or resided in a nursing home in the preceding year and had not been hospitalized in the prior 30 days.”  Also, they had to be “Medicaid enrollees for at least 365 days and have regular use of medical care.”

Hey, no selection bias introduced with those criteria, right?  But the authors didn’t stop there.

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Z-Packing

It was during my residency that the first indication of heart toxicity of antibiotics affected me personally.  The threat was related to the use of the first of the non-drowsy antihistamines – Seldane – in combination with macrolide antibiotics, such as Erythromycin causing a potentially fatal heart arrhythmia.  I remember the expressions fear from other residents, as we had used this combination of medications often.  Were we killing people when we treated their bronchitis?  We had no idea, but we were consoled by the fact that the people who had gotten our arrhythmia-provoking combo were largely anonymous to us (ER patients).

Fast forward to 2012 and the study (published in the holy writings of the New England Journal of Medicine) that Zithromax is associated with more dead people than no Zithromax.  Here’s the headline-provoking conclusion:

During 5 days of therapy, patients taking azithromycin, as compared with those who took no antibiotics, had an increased risk of cardiovascular death (hazard ratio, 2.88; 95% confidence interval [CI], 1.79 to 4.63; P<0.001) and death from any cause (hazard ratio, 1.85; 95% CI, 1.25 to 2.75; P=0.002).  Patients who took amoxicillin had no increase in the risk of death during this period. Relative to amoxicillin, azithromycin was associated with an increased risk of cardiovascular death (hazard ratio, 2.49; 95% CI, 1.38 to 4.50; P=0.002) and death from any cause (hazard ratio, 2.02; 95% CI, 1.24 to 3.30; P=0.005), with an estimated 47 additional cardiovascular deaths per 1 million courses; patients in the highest decile of risk for cardiovascular disease had an estimated 245 additional cardiovascular deaths per 1 million courses. (Emphasis Mine).

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Medical Research We Never Hear About: The Problem of Unpublished Studies

Every day, there is another medical study in the news. There’s another newspaper or TV story telling us that X can cure depression or make you thinner or cause autism or whatever. And since it’s a medical study, we usually think that it’s true. Why wouldn’t it be?

But what most people don’t realize, let alone really think about, is that there might be other studies that show that X does none of those things — and that some of those studies might never have been published.

Just this week, the journal Pediatrics released an article that perfectly demonstrates this problem. There have been a number of studies that have shown that a certain type of medication, selective serotonin reuptake inhibitors (SSRIs), can help stop the repetitive behaviors of autism, like hand-flapping or head-banging. If you were to do a search of the medical literature, as doctors and parents and patients often do, you’d think that using SSRIs is a good idea. But when researchers dug deeper, they found that there were just as many unpublished studies that showed that SSRIs didn’t help. If they had all been published (they were all good enough to be published), that same search of the medical literature would have shown that using SSRIs isn’t a good idea.

This is bad. We rely on studies to guide our decisions. What is going on?

The journals that publish articles certainly play a role. After all, it’s cooler to publish a study that has a grabby headline, that promises an answer or a cure. That’s much more likely to get readers than a study that says that something doesn’t do anything at all. But it turns out that the researchers themselves play a bigger role.

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The Difficult Science

“The mind leans over backward to transform a mad world into a sensible one, and the process is so natural and easy we hardly notice that it is taking place.” Jeremy Campbell

On the same day in November, headlines from the Wall Street Journal and the New York Times reported on the same story about a federal panel’s recommendations on consumer intake of vitamin D.

“Triple That Vitamin D Intake, Panel Prescribes” read the WSJ story;

“Extra Vitamin D and Calcium Aren’t Necessary, Report Says” stated the New York Times. (http://ow.ly/3tJMe) Since I had recently started taking vitamin D daily, I was interested in what the experts in Washington, DC were recommending.

How should you decide what advice to follow about the relationship between your diet, lifestyle, medications, health, and wellness?

Is this just another example of how the media does a terrible job? Many of us resonate with the view of media watchdog Steven Brill who said, “When it comes to arrogance, power, and lack of accountability, journalists are probably the only people on the planet who make lawyers look good.” (http://ow.ly/3tKdM)

The media does play a role here and needs to improve, but it turns out that it is really complicated to figure out what the “truth” is about diet, exercise, medicines, and your individual well being. Everybody (journalists, government panel members, scientists, patients, physicians, and nurse practitioners) needs to change.

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