Diagnostic Accuracy of the Aldosterone–to–Active Renin Ratio for Detecting Primary Aldosteronism

Abstract

Abstract Context The aldosterone–to–active renin ratio (AARR) is the recommended screening test for primary aldosteronism (PA), but prospective study data on its sensitivity and specificity are sparse. Objective To investigate the diagnostic accuracy of the AARR for detecting PA. Design Prospective diagnostic accuracy study. Setting This study was conducted from February 2009 to August 2015 at the outpatient clinic of the Department of Endocrinology and Diabetology of the Medical University of Graz, Austria. Participants Four hundred patients with arterial hypertension who were referred to a tertiary care center for screening for endocrine hypertension. Intervention Participants had a determination of the AARR (index test) and a second AARR determination followed by a saline infusion test (SIT) after 2 to 6 weeks. PA was diagnosed in individuals with any AARR ≥3.7 ng/dL/µU/mL [including a plasma aldosterone concentration (PAC) of ≥9 ng/dL] who had a PAC ≥10 ng/dL after the SIT. We did not substantially alter antihypertensive drug intake. Main Outcome Measures Primary outcome was the receiver-operating characteristic (ROC) curve of the AARR in diagnosing PA. Results A total of 382 participants were eligible for analyses; PA was diagnosed in 18 (4.7%) patients. The area under the ROC curve of the AARR in detecting PA was 0.973 (95% CI, 0.956 to 0.990). Sensitivity and specificity for a positive AARR in diagnosing PA were 100% (95% CI, 81.5% to 100.0%) and 89.6% (95% CI, 86.0% to 92.5%), respectively. Conclusions The AARR has good diagnostic accuracy for detecting PA.