A commonly used diagnostic test for primary aldosteronism, a hormone-driven condition affecting up to 30% of high blood pressure patients, is often inaccurate and may be preventing patients from receiving life-saving treatment, according to new research published in the Annals of Internal Medicine.
The study, led by Dr. Alexander Leung, an associate professor of medicine at the University of Calgary in Canada, challenges the routine use of the seated saline suppression test (SSST) for confirming primary aldosteronism diagnoses. The research team suggests that eliminating this confirmatory test could "improve diagnostic accuracy and reduce time to treatment," representing "a large paradigm shift in the field of hypertension."
Study Reveals Diagnostic Test Limitations
The clinical trial, conducted between January 2017 and August 2024, recruited 156 patients who had screened positive for primary aldosteronism. All participants underwent the SSST follow-up test, which involves administering a saline IV drip while monitoring blood aldosterone levels to confirm the diagnosis.
Critically, every patient in the study received treatment for primary aldosteronism regardless of their SSST results—either through surgical removal of an overactive adrenal gland or medication to block aldosterone hormone activity. The researchers then used patients' treatment responses as the gold standard to evaluate the SSST's diagnostic accuracy.
The results were striking: the SSST could not distinguish between patients who did and didn't respond to primary aldosteronism treatment. More concerning, a large number of patients who responded well to treatment were incorrectly classified as "normal" by the SSST.
Significant Clinical Impact of Missed Diagnoses
Primary aldosteronism involves overproduction of aldosterone, a hormone that regulates sodium and potassium levels in the bloodstream. People with this condition tend to retain salt, leading to increased blood pressure and significantly higher cardiovascular risks compared to those with standard hypertension.
Research shows that individuals with primary aldosteronism face nearly 2.6 times higher stroke risk, twice the likelihood of heart failure, 3.5 times greater chance of developing abnormal heart rhythms, and 77% increased probability of heart disease. Despite these serious health implications and the availability of excellent treatments, fewer than 1% of patients are currently diagnosed and treated due to the complicated diagnostic process.
As many as 30% of high blood pressure patients seen by heart specialists and 14% of those in primary care have primary aldosteronism, yet many never receive appropriate blood testing for the condition. Others are tested years after their initial hypertension diagnosis, by which time the condition has often caused severe health complications.
Treatment Options and Clinical Recommendations
Effective treatments for primary aldosteronism include prescription medications such as spironolactone and eplerenone, which lower blood pressure and boost potassium levels. In cases where only one adrenal gland is overproducing aldosterone, surgical removal may be recommended. Patients are also advised to follow a balanced low-sodium diet and maintain healthy weight.
The research findings suggest that confirmatory testing with the SSST "adds little to the diagnostic work-up in patients who already have a positive result on a screening test." Instead, reliance on the SSST "may misinform downstream treatment decisions and lead to missed opportunities for intervention, even in patients who would clearly respond to treatment."
Implications for Clinical Practice
The study's conclusions support a fundamental change in how primary aldosteronism is diagnosed. "The results of our study suggest that removal of routine confirmatory testing from the diagnostic care pathway for PA may help to improve diagnostic accuracy and reduce the time needed for diagnosis and treatment for most patients," the researchers wrote.
Dr. Gail Adler, an endocrinologist at Brigham and Women's Hospital in Boston, emphasized the importance of early detection: "With a low-cost blood test, we could identify more people who have primary aldosteronism and ensure they receive the proper treatment for the condition."
The research team's recommendations align with emerging guidelines suggesting that everyone diagnosed with high blood pressure should have their aldosterone levels checked, with those testing positive for primary aldosteronism receiving condition-specific treatment rather than standard hypertension management.
