Testing for Primary Aldosteronism and Mineralocorticoid Receptor Antagonist Use Among U.S. Veterans : A Retrospective Cohort Study

Abstract

Background: Primary aldosteronism is a common cause of treatment-resistant hypertension. However, evidence from local health systems suggests low rates of testing for primary aldosteronism.

Objective: To evaluate testing rates for primary aldosteronism and evidence-based hypertension management in patients with treatment-resistant hypertension.

Design: Retrospective cohort study.

Setting: U.S. Veterans Health Administration.

Participants: Veterans with apparent treatment-resistant hypertension (n = 269 010) from 2000 to 2017, defined as either 2 blood pressures (BPs) of at least 140 mm Hg (systolic) or 90 mm Hg (diastolic) at least 1 month apart during use of 3 antihypertensive agents (including a diuretic), or hypertension requiring 4 antihypertensive classes.

Measurements: Rates of primary aldosteronism testing (plasma aldosterone-renin) and the association of testing with evidence-based treatment using a mineralocorticoid receptor antagonist (MRA) and with longitudinal systolic BP.

Results: 4277 (1.6%) patients who were tested for primary aldosteronism were identified. An index visit with a nephrologist (hazard ratio [HR], 2.05 [95% CI, 1.66 to 2.52]) or an endocrinologist (HR, 2.48 [CI, 1.69 to 3.63]) was associated with a higher likelihood of testing compared with primary care. Testing was associated with a 4-fold higher likelihood of initiating MRA therapy (HR, 4.10 [CI, 3.68 to 4.55]) and with better BP control over time.

Limitations: Predominantly male cohort, retrospective design, susceptibility of office BPs to misclassification, and lack of confirmatory testing for primary aldosteronism.

Conclusion: In a nationally distributed cohort of veterans with apparent 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.

Primary funding source: National Institutes of Health.

Figure 1.

Cohort derivation and primary aldosteronism testing status, initial testing results, MRA use, and adrenalectomy status among participants who met inclusion criteria. MRA = mineralocorticoid receptor antagonist.

Figure 2.

Proportion of patients with apparent treatment-resistant hypertension tested for primary aldosteronism, by medical center (left) and index year (right). The columns depict the total number of patients with treatment-resistant hypertension (light green) and the total number with treatment-resistant hypertension who were tested for primary aldosteronism (dark green), quantified on the left y-axis. The solid black line depicts the proportion of patients with treatment-resistant hypertension who were tested for primary aldosteronism, quantified on the right y-axis.

Figure 2.

Proportion of patients with apparent treatment-resistant hypertension tested for primary aldosteronism, by medical center (left) and index year (right). The columns depict the total number of patients with treatment-resistant hypertension (light green) and the total number with treatment-resistant hypertension who were tested for primary aldosteronism (dark green), quantified on the left y-axis. The solid black line depicts the proportion of patients with treatment-resistant hypertension who were tested for primary aldosteronism, quantified on the right y-axis.