Aldosterone-to-renin ratio for diagnosing aldosterone-producing adenoma: a multicentre study

Abstract

Background: Biological diagnostic criteria for diagnosing aldosterone-producing adenoma (APA) are not well-established.

Aim: The aim of the study was to establish the best biological predictors of APA.

Methods: A prospective register was implemented in 17 secondary or tertiary hypertension centres. The inclusion criterion was one of the following: onset of hypertension before 40 years of age; history of hypokalaemia; drug-resistant hypertension (resistant to three drugs); or spironolactone efficiency on BP.

Results: Among the 338 collected cases, 192 patients had two aldosterone-to-renin ratio (ARR) determinations (after 1 hour supine and at least 1 hour upright) on the same occasion. Twenty-five patients (8.2%) had biological hyperaldosteronism and an adrenal adenoma identified by computed tomography. APA was histologically confirmed in all 12 patients who underwent surgery. Histologically proven APAs were used as the 'gold standard' in receiver operating characteristic (ROC) curve analysis. ARRs were computed with a minimum renin value set at 5 ng/L to avoid misclassification of so-called 'low-renin hypertension'. To predict an APA, the ARR area under the ROC curve was 0.93. A supine ARR cut-off value of 32ng/ng provided the highest sum of sensitivity (92%) plus specificity (92%). On the basis of an ARR≥32 ng/ng in the supine and/or upright position, sensitivity reached 100%.

Conclusion: The proposed cut-off value of 32 ng/ng for ARR (minimum renin value set at 5 ng/L) in one of two determinations had 100% sensitivity and 72% specificity with 20% positive and 100% negative predictive values for diagnosing APA.