Association of Plasma Aldosterone Concentration With Early Renal Injury Biomarkers in Primary Aldosteronism: A Propensity-Matched Comparative Study

Primary aldosteronism (PA) independently increases renal impairment risk beyond blood pressure effects. Although hyperaldosteronism is known to mediate renal injury, associations between plasma aldosterone concentration (PAC) and early kidney damage biomarkers such as retinol-binding protein (RBP) and β2-microglobulin (β2-MG) remain insufficiently explored. We investigated the association of PAC with renal function indicators—including RBP, β2-MG, albumin-to-creatinine ratio (ACR), and estimated glomerular filtration rate (eGFR)—comparing matched patients with PA and essential hypertension (EH). In this cross-sectional study, 546 PA patients and 546 propensity score-matched EH patients were assessed. Spearman correlations and multivariate regression analyses assessed PAC-renal marker associations, with interactions tested to determine differences between PA and EH groups. In PA, PAC strongly correlated with lower eGFR (r = −0.597, p < 0.001) and higher RBP (r = 0.559), β2-MG (r = 0.632), and ACR (r = 0.583), persisting after adjustment. In contrast, EH patients showed only weak correlations between PAC and eGFR (r = −0.204, p < 0.001), without links with other markers. Interaction analysis confirmed stronger PAC-biomarker associations in PA than EH (all p < 0.05). This study is the first to demonstrate robust associations between PAC and sensitive early renal damage biomarkers, especially RBP, in PA patients, distinct from matched EH patients. It highlights hyperaldosteronism's unique pathogenic role in renal impairment in PA, suggesting early biomarker monitoring and aldosterone-targeted interventions could reduce chronic kidney disease risk in PA populations.