Predictors of treatment response to mineralocorticoid receptor antagonists in primary aldosteronism: insights from the SPAIN-ALDO registry

BACKGROUND: Data on factors predicting favorable response to medical therapy in primary aldosteronism, based on Primary Aldosteronism Medical treatment Outcome (PAMO) criteria, remain limited. AIM: This study aimed to identify baseline parameters independently associated with clinical and biochemical responses to mineralocorticoid receptor antagonist (MRA) therapy after at least 6 months of treatment. METHODS: Primary aldosteronism patients from the SPAIN-ALDO registry, treated medically with MRA (or amiloride) and with available clinical and/or biochemical follow-up data after at least 6 months of therapy were included. RESULTS: A total of 402 patients (38.3% women; mean age 57 ± 11.8 years) were analyzed. Median follow-up duration was 38 months [interquartile range (IQR) 20-76]. At last visit, 55% of patients were receiving spironolactone, 44% eplerenone, and 1.2% amiloride. Among 389 patients with clinical follow-up data, 16.2% achieved complete clinical success, 65.5% partial response, and 18.3% showed no response. Complete clinical response was more likely in women, in patients with lower BMI, fewer antihypertensive medications, and higher potassium levels. Among 261 patients with biochemical follow-up data, 50.1% had complete biochemical response, 21.5% partial, and 28.4% absent. Predictors of complete biochemical response included lower baseline aldosterone concentration, higher baseline renin levels, use of spironolactone rather than eplerenone, and higher MRA doses. CONCLUSION: Early identification of primary aldosteronism and optimized titration of MRA therapy, especially with eplerenone, are crucial for improving clinical and biochemical outcomes.