ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

Endocrine Abstracts (2019) 63 P409 | DOI: 10.1530/endoabs.63.P409

Diagnostic accuracy of the aldosterone to active renin ratio in detecting primary aldosteronism: the graz endocrine causes of hypertension (GECOH) study

Stefan Pilz1, Martin Keppel2, Christian Trummer1, Verena Theiler-Schwetz1, Marlene Pandis1, Valentin Borzan1, Matthias Pittrof1, Barbara Obermayer-Pietsch1, Martin R Grübler3, Nicolas Verheyen4, Vinzenz Stepan1, Andreas Meinitzer5, Jakob Voelkl6, Winfried März5 & Andreas Tomaschitz7

1Department of Internal Medicine, Division of Endocrinology and Diabetology, Medical University of Graz, Graz, Austria; 2University Institute for Medical and Chemical Laboratory Diagnostics, Paracelsus Medical University, Salzburg, Austria; 3Department of Cardiology, Swiss Cardiovascular Center Bern, Bern University Hospital, University of Bern, Bern, Switzerland; 4Department of Cardiology, Medical University of Graz, Graz, Austria; 5Clinical Institute of Medical and Chemical Laboratory Diagnostics Medical, University of Graz, Graz, Austria; 6Institute for Physiology, Johannes Kepler University Linz, Linz, Austria; 7Bad Gleichenberg Clinic, Bad Gleichenberg, Austria.

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: We investigated the diagnostic accuracy of the AARR for detecting PA.

Design: This is a 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: We included 400 patients with arterial hypertension who were referred to our 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 two 6 weeks. PA was diagnosed in individuals with any AARR of ≥3.7 ng/dl/μU/ml (including a plasma aldosterone concentration [PAC] of ≥9 ng/dl) who had a PAC of ≥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: Eligible for analyses were 382 participants and PA was diagnosed in 18 patients (4.7%). The area under the ROC curve of the AARR in detecting PA was 0.973 (95% confidence interval [CI]: 0.956–0.990). Sensitivity and specificity for a positive AARR in diagnosing PA was 100% (95% CI: 81.5–100.0) and 89.6% (95% CI: 86.0–92.5), respectively.

Conclusions: The AARR has a good diagnostic accuracy for detecting PA.