Primary Aldosteronism Testing Rare in Patients With Treatment-Resistant Hypertension

New study findings demonstrate patients with treatment-resistant hypertension rarely get tested for primary aldosteronism.

In patients with treatment-resistant hypertension, testing for primary aldosteronism is rare and associated with higher rates of evidence-based treatment with mineralocorticoid receptor antagonists (MRAs) and better longitudinal blood pressure control.

The findings emphasized prior awareness of low adherence to guideline-recommended practices in smaller health systems. Further, the findings highlighted the need for improved management of patients with treatment-resistant hypertension.

Jordana B. Cohen, M.D., MSCE, and colleagues evaluated testing rates for primary aldosteronism and evidence-based hypertension management in patients with treatment-resistant hypertension. The team used national Veterans Health Administration (VHA) data from the VHA Corporate Data Warehouse, which included diagnostic codes, laboratory results, vital signs, and pharmacy fill records on approximately 9 million veterans.

The study group came from the Antihypertensives in Obesity Management Cohort — a study of more than 1 million veterans with incident hypertension from Jan. 1, 2000 to Dec. 31, 2017 and evidence of receiving primary care in the VHA. Investigators restricted the study population to veterans with incident apparent treatment-resistant hypertension, which they defined as either two successive blood pressures of at least 140 mm Hg (systolic) or 90 mm Hg (diastolic) at least one month apart during use of three antihypertensive agents, or receipt of four antihypertensive classes.

The primary end point was testing for primary aldosteronism. Additional end points included initiation of MRA treatment and change in systolic blood pressure over time.

Cohen and the team identified 4,277 patients who were tested for primary aldosteronism. For patients, hypokalemia (standardized HR, 1.93; 95% CI, 1.8-2.07) and higher systolic blood pressure (standardized HR, 1.43; 95% CI, 1.37-1.49) were associated with a higher likelihood of undergoing testing. Visiting a nephrologist (HR, 3.05; 95% CI, 1.66-2.52) or an endocrinologist (HR, 2.48; 95% CI, 1.69-3.63) was also associated with a higher likelihood of testing compared with primary care.

Rural location was associated with a lower likelihood of testing than nonrural location (HR, .53; 95% CI, .31-.91).

At five years of follow-up, those who were tested had an average 1.1-year shorter survival time (95% CI, .9-1.2 years) before MRA therapy initiation compared with those who did not undergo testing. Testing for primary aldosteronism was associated with a four-fold higher likelihood of subsequently starting MRA therapy compared with no testing (HR, 4.1; 95% CI, 3.68-4.55). Those with a history of hypokalemia who underwent testing were more likely to be treated with MRA (HR, 7.11; 95% CI, 6.25-8.1) than those without (HR, 4.21; 95% CI, 3.59-4.94).

Overall, the investigators observed less than 2% of patients with incident apparent treatment-resistant hypertension underwent guideline-recommended testing for primary aldosteronism. Low rates of testing may be due to barriers to testing, the team suggested.]

Additional research should be conducted to evaluate the implementation of tools to identify patients through the electronic health record and alert provider to whether they should be tested.

The study, “Testing for Primary Aldosteronism and Mineralocorticoid Receptor Antagonist Use Among U.S. Veterans,” was published online in the journal Annals of Internal Medicine.