Performance of Aldosterone-to-renin Ratio Before Washout of Antihypertensive Drugs in Screening of Primary Aldosteronism

Abstract Objective The aim of this study is to evaluate performance of aldosterone-to-renin ratio (ARR) before washout of antihypertensive drugs as a screening test for primary aldosteronism (PA). Methods This retrospective analysis included consecutive patients screening for secondary hypertension during a period from January 2017 to May 2022 at the authors’ institute. For inclusion in the final analysis, ARR had to be available prior to as well as after discontinuation of antihypertensives. Patients with ARR ≥2.4(ng/dL)/(μIU/mL) after washout proceeded to confirmatory tests. Diagnosis of PA was established based on a positive result of the confirmatory test. The diagnostic accuracy of ARR prior to the washout in predicting PA is shown as sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Results The analysis included a total of 1306 patients median age of 50.2 (41.0-59.0) years, 64.0% male. Confirmatory tests showed PA in 215(16.5%) patients and essential hypertension (EH) in the remaining 1091(83.5%) patients. In comparison to the second screening test, the first screening test (before washout of antihypertensives) yielded lower plasma aldosterone and higher renin and consequently lower ARR in both the PA and EH groups. At a cutoff of .7(ng/dL)/(μIU/mL), ARR before washout had 96.3% sensitivity, 61.2% specificity, .33 PPV, and .99 NPV. At a lower cutoff of .5(ng/dL)/(μIU/mL), the sensitivity, specificity, PPV, and NPV were 97.7%, 52.0%, .29, and .99, respectively. Conclusion ARR prior to washout of antihypertensives is a sensitive screening test for PA. Washout of antihypertensives could be omitted and further investigation for PA is not warranted if ARR is ≤ .7(ng/dL)/(μIU/mL) before washout.