Mark Cuban is a billionaire entrepreneur. He’s a star of the “Shark Tank” reality TV show. He’s arguably the savviest owner of an NBA basketball team, the Dallas Mavericks.

He’s even invested in four heath care companies.

But Mark Cuban doesn’t understand health care.

That’s the obvious conclusion after Cuban issued a series of lunkheaded tweets on Wednesday — encouraging Americans to get their blood tested every quarter — and then doubled down after being gently challenged by Charles Ornstein, a ProPublica reporter.

Ornstein’s no ordinary health care journalist; he’s a Pulitzer Prize-winninginvestigative reporter, a well-known data guru, and the past president of the Association of Health Care Journalists. But his point here was fairly conventional: More health care testing isn’t healthy. More health care isn’t healthy.

Yet Cuban grew increasingly obstinate — “You demonstrated nothing except a [lack of] faith in our healthcare systems and doctors in general,” he told Ornstein at one point — even as a growing horde of health care experts told Cuban just how wrong he was.

As Ornstein and others pointed out, there were a number of problems with Cuban’s argument. Here are three of them.

1. More health data isn’t necessarily better

Cuban’s main point paralleled arguments that he’smade — that many people have made — about the need to get as much data as possible, all the time.

You can see that conviction in Cuban’s investment portfolio, too. He’s getting data on pedestrian walking patterns. Data on how people use Twitter. Data on where NBA players are most likely to hit their shots.

In fact, Cuban’s stance seems intuitive: the more data the better, right? Especially for something as important as your health!

Also See: Apple’s New Plan For Health Care — The Doctor Will Track You Now 

But health care data operates under a unique set of rules. For one, the data is often imperfect — and the more data you collect, the more likely you’ll stumble across a misleading indicator, like a false positive.

“Getting lab tests just because you can runs the risk of the same problems that plague screening tests, like the PSA,” Shannon Brownlee told me. (Brownlee’s a senior vice president at the Lown Institute, and the author of the influential book Overtreated: Why Too Much Medicine Is Making Us Sicker.)

“You’re looking at false positives that require a lot of follow up, which involves both worry and risk of physical harm,” Brownlee added.

Here’s a visual illustration of that PSA problem: For every 1,000 men who get regularly screened for prostate cancer, about 20% of them will end up getting unneeded biopsies or even have their prostate unnecessarily removed because the data is wrong.

 

 

It’s a clear representation of why more and more groups are advising fewer PSA tests. Even the leading association of urologists — who stand to benefit financially from annual tests — said many men should stop.

And at the moment, data tracking isn’t the only problem in health care. There’s no clear path for what to do with a lot of it, too.

Several health-tech CEOs have talked to me about the challenge of capturing this “digital exhaust.” Who’s collecting it? Who’s protecting it?

And should you meet with your doctor to discuss every troubling indicator?

2. More health care often isn’t better

Cuban seemed to miss a fundamental truth about health care testing and treatment: Less is more.

Medical errors and accidents are widespread. Misdiagnoses are rampant. Every procedure carries risk.

Or as patient-safety expert Dr. Ashish Jha puts it, a hospital is “one of the most dangerous places in the world … when your loved one goes to the hospital, the likelihood that they will be harmed is unnecessarily high.”

And it’s not like regular blood testing is going to uncover some secret — at least, not yet.

“There has been extensive research on the value of getting blood tests without symptoms,” Dr. R. Adams Dudley told me on Wednesday night. “There isn’t a single study suggesting quarterly blood testing is necessary to screen for any condition.”

(Dudley’s a professor at University of California, San Francisco, director of the UCSF Center for Healthcare Value, and an award-winning health policy researcher.)

And a quarterly test can easily lead to more unnecessary treatment. Dudley walked me through the simple math of how that cascade can start:

• If a patient gets just five things checked in his blood every quarter, that’s the equivalent of 20 tests a year. (An activist patient like Cuban may be getting many more tests done.)
• Given normal variation, about 5% of tests may produce an unexpected result. That means that out of 20 tests, “even one test is expected to be abnormal, even if [the patient's] healthy,” Dudley points out.
• Although doctors may suspect that nothing’s amiss, “we are trained not to just ignore an abnormal result, but to do further testing or even treatment,” Dudley points out. “That testing or treatment always involves risks.”

3. More spending isn’t better — for any of us

America already spends much more on health carethan every comparable country.

 

 

That added health spending has been a key driver of historic deficits. It’s possibly the biggest public-policy problem facing the economy.

For various reasons, that spending growth is finally slowing down. And one positive development is that leading medical groups and oversight bodies, like the U.S. Preventive Services Task Force, are increasingly scaling back recommended screening and tests.

To put it simply, the emerging medical wisdom boils down to: Do less.

But despite no medical evidence, Cuban believes we need to be doing more. And his recommendation of four blood tests per year, if broadly adopted, would easily add billions of new spending on regular bloodwork alone.

“First, it would never be affordable to most people, so as a recommendation, it’s quite expensive,” UCSF’s Dudley said. “Since our economy is already saddled with high health care costs, [devoting] more resources to unnecessary health care, even if it never caused clinical harm, would be unfortunate.”

Why you should care

Cuban’s comments wouldn’t matter much if he was a run-of-the-mill investor, or even an average tech CEO.

But Cuban’s platform is so big — he has nearly 3 million followers on Twitter — and he announced that his debate with Ornstein perversely motivated him to further promote his bizarre, bloody agenda.

“All this got me excited to push it more,” Cuban posted on Twitter late on Wednesday. “[With] the caveat. Dont show yr doctor the results until u are ill.”

A few folks applauded Cuban’s audacity. But on balance, the billionaire’s plan left health experts kind of sick.

“It’s absolutely crazy, there’s no good that can come of it, and it makes me wonder if the guy has stock in a testing lab,” Brownlee said. “Either that or he’s secretly a vampire.”

Note: Although Cuban has invested in health companies like Validic andMobile ODT — which specialize in personal health data collection — he statedthat he has no stake in testing companies or labs that would benefit from regular blood testing.

“We know there’s a lot of harm that comes from people getting overtreated for ‘conditions’ they don’t really have that have been detected through screening,” Brownlee added.

“Why on earth would anybody want the stress of quarterly screening?”

–

 

 

Sign up for Dan’s free newsletter.

From the archives:

• Apple Wants Your Health Data. But Can HealthKit Protect It?
• Apple’s Watch Is Just Days Away. It’s Already Overhyped
• Report: Amazon May Be Planning To Jump Into Health Care.
• Health Care For $4: Are You Ready For Walmart To Be Your Doctor?