Primary aldosteronism: Aldosterone/renin ratio cut-off points

Area of Science:

• Endocrinology
• Hypertension Research
• Clinical Diagnostics

Background:

• Primary aldosteronism (PA) is a common endocrine cause of hypertension, affecting 6-12% of patients.
• The aldosterone/renin ratio (ARR) is the primary screening test for PA.
• Existing ARR cut-off points vary, necessitating population-specific reference values.

Purpose of the Study:

• Optimize ARR and aldosterone/renin concentration (ARC) cut-off points for PA screening using current methodologies.
• Evaluate the correlation and diagnostic sensitivity of ARR and ARC ratios for PA.
• Determine the prevalence of PA within the study population.

Main Methods:

• Measured plasma aldosterone concentration and plasma renin activity/concentration using radioimmunoassays and chemiluminescence assays.
• Calculated ARR and ARC ratios in 345 subjects (136 healthy, 209 hypertensive).
• Utilized ROC curve analysis to determine optimal cut-off thresholds.

Main Results:

• Confirmed a PA prevalence of 5.9% in the study population.
• Identified an optimal ARR threshold of 48.9 (ng/dL)/(ng/mL/h) and an ARC threshold of 2.3 (ng/dL)/(μIU/mL).
• Demonstrated high sensitivity (100% for both) and specificity (93.6% ARR, 90.9% ARC) with strong correlation (ρ=.83) and concordance (96.6%) between ARR and ARC.

Conclusions:

• Established new, validated cut-off values for ARR and ARC in the study population for PA screening.
• The optimized thresholds offer high sensitivity and diagnostic concordance, aiding in accurate PA diagnosis.
• Emphasized the importance of using validated reference ranges to prevent diagnostic errors in PA screening.