Intraindividual Variability of Aldosterone Concentrations in Primary Aldosteronism: Implications for Case Detection

Area of Science:

• Endocrinology
• Hypertension Research
• Clinical Diagnostics

Background:

• Primary aldosteronism is a significant, underdiagnosed cause of hypertension.
• Current screening practices may miss cases due to strict aldosterone and renin ratio thresholds.
• Intraindividual variability in screening tests contributes to underdiagnosis.

Purpose of the Study:

• To evaluate the intraindividual variability of screening aldosterone and renin levels in patients with confirmed primary aldosteronism.
• To assess the impact of this variability on case detection rates.
• To determine if current diagnostic thresholds for primary aldosteronism screening are appropriate.

Main Methods:

• Analysis of 137 screening measurements from 51 patients with confirmed primary aldosteronism.
• Measurements of aldosterone and renin were taken on different days for each patient (mean of 3 per patient).
• Calculated intraindividual variability using coefficients of variation for aldosterone and aldosterone-to-renin ratio.

Main Results:

• Significant intraindividual variability observed: 31% for aldosterone, 45% for aldosterone-to-renin ratio.
• Many patients had screening values below conventional thresholds: 49% had aldosterone < 15 ng/dL, 57% had ARR < 30 ng/dL per ng/mL·hour.
• A substantial proportion had multiple low readings, indicating consistent variability.

Conclusions:

• Aldosterone and aldosterone-to-renin ratio screening values are highly variable in primary aldosteronism.
• Current diagnostic thresholds may lead to false negatives due to this variability.
• Liberalizing screening thresholds for aldosterone and ARR could increase primary aldosteronism diagnosis rates.