THE ALDOSTERONE RENIN RATIO BASED ON THE?PLASMA RENIN ACTIVITY AND THE DIRECT RENIN ASSAY FOR DIAGNOSING ALDOSTERONE-PRODUCING ADENOMA: PP.24.471:

Background: The screening for primary aldosteronism (PA) is based on the aldosterone/renin ratio (ARR), which is calculated with the Plasma Renin Activity (PRA) as denominator. A direct measurement of active renin (DRA) is being used as an alternative to PRA, but its diagnostic performance remains uncertain. Aim of the study was to head-to-head compare the ARR based on PRA (ARR-P) to on DRA (ARR-D), at baseline and post-captopril, for identifying aldosterone-producing adenoma (APA) in a subset (251 patients) of the PAPY Study. Methods: The area (AUC) under the ROC curves was employed for estimating the accuracy of ARR-D and ARR-P for identifying APA and for between tests comparison.?? Results and Conclusions: PA was found in 13.2% patients, 6.4% of whom had APA and 6.8% idiopathic hyperaldosteronism (IHA); 218 (86.8%) had primary hypertension. The PRA and the DRA showed a weaker correlation at baseline (r = 0.26, p < 0.0001) and a stronger post-captopril (r = ?0.65, <0.0001). Both the ARR-D and the ARR-P were useful for identifying APA, as shown by AUC under the ROC curves (0.870 ± 0.058 and 0.973 ± 0.028, respectively) > 0.50 (both p < 0.0001); at a between-test comparison the ARRs did not differ significantly. For the ARR-D the optimal cut-off value for identifying APA was 27.3, remarkably similar to that previously determined for the ARR-P. Thus, the ARR-D represents a reasonable alternative to the ARR-P for detecting APA