NT-proBNP and its association with autonomous aldosterone production in primary aldosteronism

Introduction: Autonomous aldosterone production and mineralocorticoid receptor activation are key pathophysiologic mechanisms underlying primary aldosteronism (PA). N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a sensitive biomarker for evaluating cardiac stress and fluid status. This study aimed to investigate the association between NT-proBNP and renin-independent autonomous aldosterone production, as well as potential confounding factors. Methods: We conducted a retrospective cohort study of 443 patients with PA who underwent both a captopril challenge test (CCT) and measurement of NT-proBNP. The CCT was used to evaluate the degree of renin-independent aldosterone production, and the association between NT-proBNP and renin-independent aldosterone production was assessed using multivariable regression analysis. Echocardiography was performed to evaluate cardiac structure and function. Results: After multivariable regression analysis, post-CCT plasma aldosterone concentration (PAC) and aldosterone-renin ratio (ARR) were identified as independent predictors of NT-proBNP levels. In addition, female sex and lower body mass index (BMI) were significantly associated with higher NT-proBNP levels, compared to men or individuals with higher BMI. NT-proBNP also remained a significant predictor of increased left ventricular mass index and impaired diastolic function after adjustment across multiple models, underscoring its strong association with cardiac remodeling and dysfunction in patients with PA. Conclusion: Higher post-CCT PAC and ARR were independently associated with NT-proBNP in patients with PA, indicating a pathophysiological link between renin-independent aldosterone production and cardiac stress. Sex and BMI significantly influenced NT-proBNP concentrations, underscoring the importance of considering these factors when interpreting NT-proBNP levels in clinical practice.