Test characteristics of the aldosterone-to-renin ratio as a screening test for primary aldosteronism

Background:The aldosterone-to-renin ratio (ARR) is a widely used screening test for primary aldosteronism. Current guidelines recommend a cut-off value of 91pmol/mU. Studies on its sensitivity, specificity, reproducibility and the role of medication have been conflicting. We prospectively assessed the test characteristics of the ARR and the effect of combination antihypertensive treatment.Methods:In 178 patients with persistent hypertension despite the use of at least two antihypertensives, plasma renin and aldosterone were assessed twice within an interval of 4 weeks. All patients underwent an intravenous salt loading test. A posttest plasma aldosterone exceeding 235pmol/l was considered diagnostic for primary aldosteronism. ARR was repeated after 4 weeks of standardized treatment with a calcium channel blocker and/or -adrenergic-receptor blocker.Results:The prevalence of primary aldosteronism was 15.2%. The median ARR was 35.0 (interquartile range 16.2-82.0) in primary aldosteronism versus 7.1 (2.2-17.5) pmol/mU in essential hypertensive patients (P