[Analysis of characteristics of renin, aldosterone and aldosterone/renin ratio in patients with aldosterone-producing adenoma].

OBJECTIVE

To characterize the plasma renin activity (PRA) and plasma aldosterone concentration (PAC) and aldosterone/renin ratio (ARR) in patients with aldosterone-producing adenoma (APA).

METHODS

We retrospectively analysed the data of PRA, PAC and ARR from 80 patients with APA, 70 patients with essential hypertension (EH) and 26 individuals with normal blood pressure (NBP). Patients with hypertension were further divided into taking anti-hypertensive drug group (D) and non drug treatment group (ND). All participants received at least one following tests:ARR screening test, supine-upright position test and saline load test.Receiver-operating characteristic (ROC) analysis was used for exploring the best cut-off value of ARR and low PRA.

RESULTS

The median and percentages of PRA (ng×ml(-1)×h(-1), 1 ng×ml(-1)×h(-1) = 1 µg×L(-1)×h(-1)), PAC (ng/dl, 1 ng/dl = 27.7 pmol/L) and ARR (ng×dl(-1)/ng×ml(-1)×h(-1)) between NBP and EH (ND) groups showed no differences.Over 90% supine PRA ≥ 0.52 and 100% upright PRA ≥ 0.52 in the above two groups. On the contrary, 90% APA (ND) patients upright PRA <0.52. The lowest supine and upright ARR in APA (ND) patients was ≥ 24.2 and ≥ 37.5 respectively. ROC analysis suggested that the best screening cut-off values for APA were supine ARR ≥ 26.0, upright ARR ≥ 37.0; and low PRA cut-off value for APA were supine PRA <0.50 and upright PRA < 0.63 respectively. The sensitivity and specificity for APA diagnosis were about 88.2% and 61.5% when PAC ≥ 10.0 after saline load test.

CONCLUSIONS

The distinguishing features of PRA, PAC and ARR can be used as a diagnostic indexs for the exclusive diagnosis of APA in various clinical tests. And low PRA cut-off values exist in APA patients.