Screening Rates for Primary Aldosteronism in Resistant Hypertension: A Cohort Study.

Resistant hypertension is associated with higher rates of cardiovascular disease, kidney disease, and death than primary hypertension. Although clinical practice guidelines recommend screening for primary aldosteronism among persons with resistant hypertension, rates of screening are unknown. We identified 145 670 persons with hypertension and excluded persons with congestive heart failure or advanced chronic kidney disease. Among this cohort, we studied 4660 persons ages 18 to <90 from the years 2008 to 2014 with resistant hypertension and available laboratory tests within the following 24 months. The screening rate for primary aldosteronism in persons with resistant hypertension was 2.1%. Screened persons were younger (55.9±13.3 versus 65.5±11.6 years; P<0.0001) and had higher systolic (145.1±24.3 versus 139.6±20.5 mm Hg; P=0.04) and diastolic blood pressure (81.8±13.6 versus 74.4±13.8 mm Hg; P<0.0001), lower rates of coronary artery disease (5.2% versus 14.2%; P=0.01), and lower serum potassium concentrations (3.9±0.6 versus 4.1±0.5 mmol/L; P=0.04) than unscreened persons. Screened persons had significantly higher rates of prescription for calcium channel blockers, mixed α/β-adrenergic receptor antagonists, sympatholytics, and vasodilators, and lower rates of prescription for loop, thiazide, and thiazide-type diuretics. The prescription of mineralocorticoid receptor antagonists or other potassium-sparing diuretics was not significantly different between groups (P=0.20). In conclusion, only 2.1% of eligible persons received a screening test within 2 years of meeting criteria for resistant hypertension. Low rates of screening were not due to the prescription of antihypertensive medications that may potentially interfere with interpretation of the screening test. Efforts to highlight guideline-recommended screening and targeted therapy are warranted.