The following is a summary of “Aldosterone, Renin, and Aldosterone-to-Renin Ratio Variability in Screening for Primary Aldosteronism,” published in the January 2023 issue of Endocrinology & Metabolism by Ng, et al.

To check for primary aldosteronism (PA), the plasma aldosterone concentration (PAC), renin, and the aldosterone-to-renin ratio (ARR) were employed. There was no information on ARR variability computed using direct renin concentration (DRC). However, there was significant intra-individual variability in PAC and ARR using plasma renin activity in the context of typical antihypertensive medication. Therefore, for a study, researchers sought to characterize the intra-individual variability of PAC, DRC, and ARR in individuals with and without PA in the absence of interfering drugs.

Patients with hypertension who had at least two ARR measures while off interfering medicines were recommended for PA examination. From May 2017 to July 2021, the study was carried out at a tertiary center’s endocrine hypertension service. Variability of the PAC, DRC, and ARR was determined using the coefficient of variation (CV) and percent difference (PD).

Analysis of 223 individuals, including 162 with verified PA, showed substantial variability, with sample CVs of 22-25% in the PAC and 41% to 42% in the DRC and ARR in both the PA and non-PA groups. The analysis included 223 patients, with a median age of 52 years and a gender ratio of 55%. The level of variability was significantly more than the analytical CV of the tests. Sixty-two patients (38%) who had PA had at least one ARR below the first-line screening threshold of 70 pmol/L:mU/L (2.4 ng/dL:mU/L).

A significant number of patients undergoing PA investigation experienced significant intra-individual variability in PAC, DRC, and, consequently ARR. The results supported the requirement for at least 2 ARR before PA was disregarded or subjected to more research.