January 13, 2020

Low-value medical tests can cause a "cascade" of follow-up treatments that can ultimately lead to poorer health outcomes, Ishani Ganguli, an internist at Brigham and Women's Hospital, writes for the Washington Post. Ganguli explains why doctors still order tests like these, despite knowledge that they can backfire.

How a study on inappropriate imaging orders should inform your strategy to curb unnecessary testing

A medical cascade

One afternoon, Ganguli's learned that her patient, Lily, had been administered an electrocardiogram (EKG) before a minor procedure "just to be safe."

Doctors found that the EKG was a little off, and then the tests and treatments continued from there.  "Lily … felt fine. No chest pain. No trouble breathing. But now that the irregularity was out there, the [original] procedure would be delayed until we had answers," she writes.

After one so-so blood test result, multiple calls to an anesthesiologist, 14 emails, and a stress test, Lilly's condition was the same, Ganguli writes.

The incident reminded Ganguli of the book, "If You Give a Mouse a Cookie." The book "is a cautionary tale about the downstream consequences of a single, seemingly innocuous decision," Ganguli writes. "You gave the mouse the cookie. Naturally, he wanted a glass of milk to go with it. Before long, the mouse was moving in and sharing your ­Netflix password," Ganguli explains.

In medicine, medical tests can set off a similar chain of events, Ganguli contends. "A medical test spurs a 'cascade' of phone calls, office visits, tests and treatments, each a logical, even inevitable, progression from the one before," Ganguli writes.

To be fair, this is "how medical testing is supposed to work," Ganguli writes. But the problem is that all of the tests have their cons, including "false positives and incidental findings." Some of the tests have low value overall, meaning the benefit of running the tests is minimal.

The problem with low-value tests

As a result, the downsides of medical testing, including "cost, time, stress, pain from unnecessary biopsies, and overdiagnosis," can often override the benefits, Ganguli writes.

Research shows that low-value medical services are behind up to $101.2 billion in health care spending bloat—and that figure "does not even include the costs of cascades" of services that stem from the initial low-value service, according to Ganguli.

But doctors keep ordering them, Ganguli notes.

For instance, research shows that the low-value, preoperative EKGs do nothing to improve patients' health or reduce complications from the procedure. However, Ganguli and her team found that, for every 100 patients who got the preoperative EKG, there were 11 extra tests, treatments, office visits, hospitalizations, and diagnoses in the following three months. All of that extra care ended up costing 10 times that of the initial EKG, Ganguli contends.

How common are cascades?

To see how common these incidents were, Ganguli and her team surveyed 400 generalists from across the country.

In total, 398 said that they had seen cascades of treatment spin out of incidental findings.  

The majority of doctors also said they've seen cascades cause psychological, financial, or physical harm to patients multiple times per year, Ganguli notes. "The doctors were also affected themselves. Most had experienced wasted time and effort, frustration, or anxiety from cascades," she writes.

But if cascades cause so much harm, why are they still so common?

"Cascades are common because incidental findings are common," she writes. She adds, "[O]nce that result is there, it is hard to look away," Ganguli writes.

Meanwhile, almost 50% of the doctors that responded to the survey said they did not think their most recent cascade had actually required the further medical testing that took place. "Instead, they felt they were following the norms of the medical community or shielding against a potential lawsuit," according to Ganguli.

Patients and doctors alike sometimes are swayed to go for more testing due to concerns that their case might be "that one time in a thousand when that tiny speck turned out to be cancer," according to Ganguli.

What can the medical community do about cascades?

To avoid cascades, Ganguli contends that doctors need to set expectations with patients about the type of information these tests could reveal and take action to work with patients to decide on next steps based on evidence.

"To extend the analogy past its breaking point: Often, you should just say no to the cookie. Other times, call it quits after the glass of milk. And be prepared, every so often, to add another profile to your Netflix account" (Ganguli, Washington Post, 1/5).

Cheat sheets: Evidence-based medicine 101

Been a while since your last statistics class? It can be difficult to judge the quality of studies, the significance of data, or the importance of new findings when you don't know the basics.

Download our cheat sheets to get a quick, one-page refresher on some of the foundational components of evidence-based medicine.

Get all 6 Cheat Sheets
Download Now

Topics