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

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.

To investigate the diagnostic accuracy of the AARR for detecting PA.

Prospective diagnostic accuracy study.

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.

Four hundred patients with arterial hypertension who were referred to a tertiary care center for screening for endocrine hypertension.

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.

Primary outcome was the receiver-operating characteristic (ROC) curve of the AARR in diagnosing PA.

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.

The AARR has good diagnostic accuracy for detecting PA.