A new study highlights a chicken-or-the-egg scenario in blood pressure management: Testing for a disease that's associated with difficult-to-control blood pressure isn't happening, possibly because providers think it's rare or unwieldy, but if more people were tested, experts say we'd discover it's not rare at all.

The findings are frustrating but not surprising, says co-senior author J. Brian Byrd, M.D., M.S., an assistant professor and cardiologist at the Michigan Medicine Frankel Cardiovascular Center. Byrd, an expert on hypertension, worked with several colleagues at the University of Pennsylvania and Stanford University.

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"We're all taught in medical school that if a patient has high blood pressure and low levels of potassium in the blood, or if a patient isn't seeing improvement after blood pressure treatment, you should check for primary aldosteronism," Byrd says. "It's universally taught that this is a definitive cause of high blood pressure in some people, so we wanted to see how commonly this testing is done."

Byrd and colleagues reviewed data from military veterans diagnosed with treatment-resistant hypertension at a Veterans Health Administration facility between 2000 and 2017. They found that fewer than 2% of the people who should've been evaluated for primary aldosteronism were tested. The chances of receiving a needed evaluation were higher when the patient also saw a specialist such as a nephrologist or an endocrinologist to discuss their hypertension.

The most recent blood pressure guideline, from the American Heart Association and American College of Cardiology, recommends testing for the condition in the same situations Byrd said are taught in medical schools.

"There's an educational gap there where some physicians may think it's too complicated to test people for this, or don't know they should be thinking about testing people," Byrd explains. "The most important take-home message for clinicians is: if you're really struggling to control a patient's blood pressure, consider getting a hypertension expert involved who has special training."

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In his clinic, Byrd has seen many patients who hadn't yet been diagnosed with primary aldosteronism, which means blood pressure continued to be uncontrolled, putting them at risk of strokes or heart attacks.

"The frustrating part is that there are effective treatments for primary aldosteronism," Byrd says. "But if no one diagnoses it, it can't be treated, and it's also harder to study primary aldosteronism when it's so rarely diagnosed."

Byrd says current estimates suggest that around 20% of people with uncontrolled hypertension despite taking three blood pressure medications may actually be struggling with this treatable disorder.

Management of primary aldosteronism depends on the type diagnosed, and may include medications to block the effect of aldosterone in the adrenal gland, or surgery to remove one of the two adrenal glands.

In addition to encouraging conversations with specialists when dealing with uncontrolled blood pressure, the researchers suggest exploring technology to help solve this problem. That could include an automatic alert prompted in patients' electronic health record when they meet conditions to warrant an evaluation for primary aldosteronism, Byrd says.

Paper cited: "Testing for Primary Aldosteronism and Mineralocorticoid Receptor Antagonist Use Among U.S. Veterans." Annals of Internal Medicine. DOI: 10.7326/M20-4873