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Testing for Primary Aldosteronism and MRA Use Among US Veterans
Quick Takes
- Because of the very high risk of cardiovascular events compared to primary hypertension, the importance of screening for primary aldosteronism has been emphasized for years.
- While the US Veterans results are low at 1.6%, health systems in California, Illinois, and New York testing rates are <3%.
- The incidence of primary aldosteronism in persons undergoing confirmatory testing with 24-hour urinary aldosterone levels after sodium loading is 11% in normotensives and about 20% in those with treatment-resistant hypertension.
Study Questions:
What is the testing rate for primary aldosteronism and evidence-based hypertension management in patients with treatment-resistant hypertension?
Methods:
A retrospective observational cohort study was conducted in 269,010 US Veterans from 2000-2017 with apparent treatment-resistant hypertension. Treatment-resistant hypertension was defined as two blood pressures (BPs) ≥1 month apart of at least systolic BP 140 mm Hg or diastolic BP 90 mm Hg while on three antihypertensive agents, one of which is a diuretic, or hypertension requiring four antihypertensive drug classes. The primary outcome was the rates of primary aldosteronism testing (plasma aldosterone–renin) and the secondary endpoint was the association of testing with evidence-based treatment using a mineralocorticoid receptor antagonist (MRA) and the longitudinal systolic BP. Exclusion criteria included advanced chronic kidney disease, and those with a diagnosis of primary aldosteronism or who received MRA before meeting criteria for treatment-resistant hypertension.
Results:
Median age was 65 years and younger in those who were tested, mean BP was 140/79 mm Hg, and about 50% were obese. Antihypertensive use: 81% angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker, dihydropyridine calcium channel blocker in 39%, thiazide (or like) in 59%, and beta-blocker in 64%. Of those with treatment-resistant hypertension, provider specialty for index visit was primary care in 88%, nephrology in 1%, endocrinology in <1%, and cardiology in 10%; 65% of physicians had an academic affiliation and 7% were in a rural location. 4,277 (1.6%) patients who were tested for primary aldosteronism were identified (testing rates ranged from 0-6%). An index-visit with a nephrologist (hazard ratio [HR], 2.05; 95% confidence interval [CI], 1.66-2.52) or an endocrinologist (HR, 2.48; 95% CI, 1.69-3.63) was associated with a higher likelihood of testing compared with primary care. Testing was associated with a four-fold higher likelihood of initiating MRA therapy (HR, 4.10; 95% CI, 3.68-4.55) and with better BP control over time.
Conclusions:
In a nationally distributed cohort of veterans with treatment-resistant hypertension, testing for primary aldosteronism was rare and was associated with higher rates of evidence-based treatment with MRAs and better longitudinal BP control. The findings reinforce prior observations of low adherence to guideline-recommended practices in smaller health systems and underscore the urgent need for improved management of patients with treatment-resistant hypertension.
Perspective:
The US Veterans experience in treatment-resistant hypertension likely reflects the underutilization of simple screening for primary aldosteronism in the United States. How important is that? Primary aldosteronism is associated with a four- to 12-fold increased risk for atherosclerotic cardiovascular disease and arrhythmias compared with primary hypertension and can be effectively treated with MRAs or surgery when appropriate. The American College of Cardiology/American Heart Association and Endocrine Society recommend aldosterone/renin screening in those with treatment-resistant hypertension and those with hypertension and hypokalemia.
Clinical Topics: Prevention, Hypertension
Keywords: Aldosterone, Angiotensin Receptor Antagonists, Angiotensin-Converting Enzyme Inhibitors, Antihypertensive Agents, Blood Pressure, Calcium Channel Blockers, Dihydropyridines, Diuretics, Hyperaldosteronism, Hypertension, Hypokalemia, Mineralocorticoid Receptor Antagonists, Nephrology, Obesity, Primary Prevention, Veterans
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