Cutoff Values of Aldosterone and the Aldosterone-Renin Ratio for Predicting Primary Aldosteronism in Patients with Resistant Hypertension: A Real-Life Study

Abstract

Primary aldosteronism (PA) is commonly associated with resistant hypertension. Biochemical tests can be clinically useful in the screening and diagnosis of primary aldosteronism. This study aimed to identify the cutoff values of aldosterone levels (A) and the aldosterone-renin ratio (ARR) for an accurate prediction of PA in patients with apparent resistant hypertension in a real-life scenario. This database-based study included a historical cohort of male and female patients with apparent resistant hypertension, aged 18 years or older and surveyed for PA in a specialized center from 2008 to 2018. Aldosterone and plasma renin activity (PRA) or the plasma renin concentration (PRC) were measured in the treated hypertensive patients. The patients with positive screening results were subsequently referred to the endocrinology department for confirmatory tests. The patients with confirmed PA were included in the case group, and the others remained as controls. Receiver-operating characteristic (ROC) curves were used to identify the cutoff points for aldosterone and the ARR, thereby analyzing their sensitivity and specificity for confirmed PA. Among the 3464 patients (59 ± 13 years old, 41% male) who had apparent resistance hypertension screened, PA was confirmed in 276 individuals (8%). A ≥ 16.95 ng/dL (95% CI: 0.908-0.933) had an odds ratio of 6.24 for PA, while A/PRA ≥ 29.88 (95% CI: 0.942-0.984) or an A/PRC ≥ 2.44 (95% CI: 0.978-0.990) had an odds ratio of 216.17 for PA diagnoses. Our findings suggest that a positive PA screening with aldosterone ≥ 17 ng/dL associated with A/PRA ≥ 29.88 or an A/PRC ratio of ≥2.44 should be sufficient to confirm the diagnosis of PA without confirmatory testing.

Keywords: aldosterone; aldosterone–renin ratio; apparently resistant hypertension; primary aldosteronism; reference value; secondary hypertension.

Figure 1

Flow chart of the protocol.