Riding the health news roller coaster with a questionable kidney stone cure

Kevin Lomangino is the managing editor of HealthNewsReview.org. He tweets as @KLomangino.

Roller coaster rideSick of riding the health news merry go round, where “good for you/bad for you” health advice changes from week to week based on shoddy reporting of preliminary research?

How about a ride on the health news roller coaster instead?

This week, there were dozens of stories carrying the sensational claim that riding a roller coaster at Disney World could help you pass a kidney stone.

Here’s a sampling of the Google search results:


The stories were based on a study led by a pair of researchers at Michigan State University. The scientists apparently were intrigued by the tale of a man who reported passing kidney stones on several different occasions while riding the theme park’s Big Thunder Mountain Railroad.  They set out to test the ride as potential therapy by tucking a model kidney in their backpack, then seeing whether stones could be coaxed into passing during the ride.

The news stories all hailed the experiment as a success, citing a 64% passage rate as proof that rollercoasters were beneficial for kidney stones.

Where did this story come from? Check the news release

The narrative of all of the stories I read was nearly identical to that of a Michigan State news release and an accompanying video (embedded below) which concluded: “For the price of a ticket to an amusement park, patients saved five to ten thousand dollars for hospital treatment, and it’s a whole lot more fun.”

But that’s certainly not the whole story, nor even a reasonably close approximation of what patients and the public would want to know about this preliminary study and this topic.

To get that broader perspective, journalists would have had to contact an expert who wasn’t affiliated with the research. And precious few of the many stories about the study took the time to perform this basic journalistic due diligence.

Expert says the study “didn’t show anything clinically useful”

It took me about 10 minutes’ worth of investigating to find and connect with David S. Goldfarb, MD, a kidney stone expert at New York University, who told me he’d been sent the story about 50 times via Twitter, email and Facebook — but that he hadn’t yet heard from any journalists.

“This is crazy,” he told me, referring to the study and the news coverage it received. “Completely nuts.”

Goldfarb admitted to being impressed and perhaps a little bit jealous at the media frenzy these researchers were able to generate with their roller coaster study. But from a patient care standpoint, he said, “they didn’t show anything clinically useful.”

The study says that stones were considered “passed” if they traveled from the kidney to a point where the kidney meets the ureters (the uretopelvic junction). But Goldfarb said that kidney stones typically become painful when they get stuck lower down in the ureters themselves and block the flow of urine, setting off an inflammatory cascade. Passage through the ureter wasn’t something that the researchers assessed in this study.

“For this to be of any use, you’d want to know that the stone passes all the way from the kidney through the ureter to the bladder,” he said.

And that’s assuming that the backpack kidney simulator used in the study is even a valid representation of what happens in a real person — something Goldfarb said was far from proven.

Why the “kidney in a backpack” might not be reliable

According to a reference cited by the researchers, the kidney simulator used in the study was developed and validated to train urologists in uretoscopy, a procedure that involves snaking a flexible tube up the urinary tract to visualize and remove kidney stones. It was remolded in silicone for the roller coaster study,  but never validated as a model of how kidney stones might behave as they move through the urinary tract in people.

“This has never been correlated with a human phenomenon,” Goldfarb said.

It’s not hard to see how this could be a big problem when translating the results to actual humans. The forces at work in a real human kidney might be far different from those in the silicone look-alike that the researchers created with a 3-D printer.

That doesn’t mean that roller coasters are useless as a kidney stone therapy, merely that it’s foolish to make any strong statements without proof that the model reliably reflects what happens in a real kidney.

Lack of such proof didn’t stop global news media from trumpeting roller coasters as the latest kidney stone “cure,” or passing along the researchers’ strong recommendation for stone patients to ride roller coasters.

Many news outlets did include some boilerplate language about more research being needed and some general limitations of the kidney model (nothing as specific as what Goldfarb told me). But among the many stories I read, only CNN’s included a skeptical take from an independent urologist, Dr. Elizabeth Kavaler at Lenox Hill Hospital.

“It’s an amusing article,” she said, according to CNN, “but I can’t really tell how it’s going to impact my practice or help me with patients. I think it’s pretty crazy. Whether or not they need to go on a roller coaster seems a little extreme to me.”

Sex might be a better alternative than a roller coaster

For his part, Goldfarb said he’s not sending any of his patients on a roller coaster either, and instead recommends “a beer and a bath” — anything relaxing, along with some Aleve — for patients who need to pass a stone.

Another intriguing option? Sexual intercourse. Engaging in sex 3-4 times per week promoted stone passage in a recent clinical trial of Turkish men, Goldfarb said.

And while that’s not his first-line option, he says the evidence supporting the approach — a randomized controlled trial involving actual humans — is much stronger than the evidence from the “kidney in a backpack” study.

The caveat? The partners of the men involved in the study might not agree that the benefits were worth it.

“Did they get informed consent from the wives?” Goldfarb wonders.

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