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The US Preventive Services Task Force: what it is and why vendors hate it

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Google on “Wellness vendor compliance with US Preventive Services Task Force guidelines” and here’s what you’ll see:

No results found for “Wellness vendor compliance with US Preventive Services Task Force Screening Guidelines”.


And there’s a reason for that. Most wellness vendors are out of compliance. Now, re-google that phrase sans quotation marks. Most of the front-page “hits” are me complaining how wellness vendors are out of compliance, with Bravo being the one that comes up first.  Another hit has Wellsteps saying:

The U.S. Preventative [sic] Services Task Force has established guidelines that indicate when it is appropriate to get screened, based on age, gender, and the presence of risk factors. It is NOT recommended that an entire employee population be screened every year.

And that’s an accurate assessment, a rare instance of Wellsteps being honest (under duress, of course). You might say, well, at least they’re in compliance…but ironically Wellsteps got outed for flouting these very same guidelines about two months after they posted this paean to the USPSTF.

In sum, the USPSTF is the “gold standard” for all things prevention, and wellness vendors are in the business of all things prevention. One would therefore assume the wellness industry would be in sync with the USPSTF prevention guidelines.  This posting (with two more to follow) explains how and why most aren’t, starting with a few basics.


Q: What exactly is the US Preventive Services Task Force?

This excerpt comes right off the USPSTF website, but given the apparent widespread vendor ignorance of USPSTF recommendations, perhaps vendor firewalls block their website.  As a public service to the wellness industry, I’ll cut-and-paste it here:

Created in 1984, the U.S. Preventive Services Task Force is an independent, volunteer panel of national experts in prevention and evidence-based medicine. The Task Force works to improve the health of all Americans by making evidence-based recommendations about clinical preventive services such as screenings, counseling services, and preventive medications. All recommendations are published on the Task Force’s Web site and/or in a peer-reviewed journal.

The government relies on the USPSTF to determine what should get 100% covered, to encourage prevention.


Q: What exactly is screening and how does it differ from testing?

A doctor or nurse practitioner might run a diagnostic test on a patient who should have one for clinical reasons. Like a doctor might say: “Your cholesterol was high last time, so we should test it again.” Or “You are overweight and have a family history, so I’d like to test you for diabetes.”

By contrast, a screen uses those very same tests (plus often a whole bunch of squirrelly ones) — but applies them to everyone, not just people who are indicated for them. Screening is a hunt for hidden disease in seemingly healthy, usually across an entire company, and screening vendors often get very excited when they can report how sick the employees are. This is called “hyperdiagnosis.” One vendor, Compass Health, calls this hyperdiagnostic process “I Feel Fine Syndrome.” They insist that feeling fine means you are probably sick, except that you haven’t been diagnosed yet. They’ve even trademarked the term. Think I’m making this up?

compass health title I feel fine syndrome

However, the fact is that, with a few clear exceptions like Pap tests, blood pressure, and the occasional cholesterol/glucose screen, the entire practice of screening is highly controversial. In Switzerland, for example, mammogram screens are no longer recommended at all. (You can get mammograms as a test, just not a screen.)  The problem of overscreening and hyperdiagnosis is so widespread that one of my Quizzify colleagues wrote an entire, excellent, book on the futility and harms of using screens to hunt for diseases in an asymptomatic, generally well population.


Q: How does the USPSTF rate screens?

Grades are A,B,C, and D (and “I” — not enough evidence).  They publish a summary recommended list of “A” and “B” screens.  “C” screens are recommended for “for selected patients under individual circumstances,” a level of nuance requiring clinical competence far beyond the pay grade of most wellness vendors.

Note among other things that only a few screens are recommended as “A” for all adults, like blood pressure.  Other are recommended only for people in certain age groups and/or with certain risk factors, like aortic aneurysm screening.  (Nonetheless, plenty of vendors offer those screens on everyone, as long as the employer will pay for them.)

An example of a “D” would be a prostate (PSA) test, which is a vendor favorite. Even the inventor of the test says not to use it as a screen because it misses a lot of cancers and “finds” a lot of cancers that aren’t there.  Last time I got screened, I specifically asked the vendor, Interactive Health, not to do a PSA because they are so unreliable, but the vendor did one anyway, along with about 40 other tests that are not recommended as screens.


Q: Whoa! You said the Swiss don’t like mammograms. Are you saying we shouldn’t encourage employees to get mammograms?

No. The USPSTF says employees over 50 should get them every two years.  These are screening recommendations. That means for women with no risk factors. If you have reason to believe you carry the BRCA gene or are at high risk otherwise (such as having had breast cancer in the past, or a family history), then by all means discuss a different schedule with your doctor.


Q: So the Swiss are wrong?  The Swiss are never wrong about this kind of thing.

They may not be. Really, no one knows.  And there is nothing to “know.” Breast cancer screening, like all other screening, involves a trade-off between benefits and harms. The USPSTF reaches a different conclusion than Switzerland does because “ties go to the runner” for USPSTF. If evidence isn’t compelling enough one way or the other, they draw the line in favor of more frequent screening.

If your average person understood biostatistics, the USPSTF wouldn’t have to publish recommendations.  Each person might look at the same data on harms and benefits and decide, presumably in consultation with their doctor, whether to shake the dice on testing and followup. Guys, would you get a PSA screen if there was a 1-in-20 chance that the follow-up would possibly ruin your life, but a 1-in-1000 chance that your life would be saved?

We can all reach different conclusions there. Women should see the next Q&A for the analogous screen.


Q: How can something as simple as screening cause harm?

Go back to that article on Switzerland and you’ll see some incredible data about overscreening harms from mammography. For every breast-cancer death prevented in women over a 10-year course of annual screening beginning at 50 years of age, 490 to 670 women are likely to have a false positive mammogram with repeat examination; 70 to 100, an unnecessary biopsy; and 3 to 14, an overdiagnosed breast cancer that would never have become clinically apparent.

Those are examples of the numerical harms of over-screening. Some of the harms are numerical, while others can’t be quantified. The ones quantified above include:

  • False positives, causing people to seek unnecessary, and possibly harmful, follow-up;
  • The harms or unreliability of the followup itself, such as prostate, breast or lung biopsies;
  • The possibility that the biopsy will itself be a false positive.

Other harms of screening that can’t be quantified include:

  • False negatives, causing people to become complacent if they see unexplained symptoms;
  • The possibility of missing the most-aggressive and fastest-growing tumors that grow between screening sessions, but catching those slow-growing or otherwise clinically insignificant tumors which may not do harm;
  • “Detecting” many cancers that are better left undetected because they will do no harm;
  • “Detecting” things you can’t or shouldn’t do anything about (for instance, prostate cancer is increasingly “treated” by doing nothing)
  • Findings that are not the focus of the screens, called “incidentalomas,” that have a very high chance of being clinically insignificant;
  • The harms of screening itself, such as radiation, or physical harm, as in colonoscopies;
  • The psychological harm of being told you’re sick when you aren’t, which vendors love to do — see the Nebraska case study, another perfect example of the aforementioned hyperdiagnosis.

Q: But most of these tests are at least 90% accurate, so aren’t misses rare?

There is also widespread misunderstanding of the arithmetic of misses. Consider this example.

Excluding people already diagnosed with coronary artery disease or already known to be at high risk for whom screenings are redundant, maybe 1 in 1000 employees will suffer a heart attack this year. Let us assume that there is a magic blood test, far beyond today’s technology and predictive potential, that would be 90% accurate for finding the unsuspecting employees who will suffer a heart attack this year.

If an employee tests positive, his odds of a false positive are not 10%, as would be expected if a test is 90% accurate. Quite the contrary, despite the magical accuracy of this hypothetical screen, testing 1000 employees will result in about 100 positive findings, only one of whom will have a heart attack. Meanwhile, the other 99 employees testing positive will be subject to unnecessary follow-up tests, drugs, and possibly stents.

That’s why it costs a million dollars to prevent a heart attack via screening.

While patients could be expected not to understand this arithmetic, even doctors appear to vary greatly in their understanding of false-positive arithmetic.  If doctors, following many years of college, medical school and supervised training, cannot understand these harms and this arithmetic, how is it possible that wellness vendors could do better, despite the industry’s lack of requirements for education, training, testing, licensure, compliance, and ethics?


Coming up: Part 2 — Wellness vendors vs. the USPSTF

 


3 Comments

  1. Mitch Collins says:

    Excellent.

    Like

  2. Cathy Cather says:

    We Humans have a voracious desire to control death. It’s instinctive. Screening is a very seductive pacifier.

    And, they result in millions of people on worthless medications.

    Like

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