SUN-240 - Renin Response and Clinical Outcomes in Primary Aldosteronism: Adrenalectomy Versus Mineralocorticoid Receptor Antagonist Therapy

Context

Primary aldosteronism (PA) is treated with adrenalectomy (ADX) or mineralocorticoid receptor antagonists (MRA), but comparative renin-based outcome data remain limited. We compared biochemical and clinical outcomes after ADX versus MRA and identified factors associated with higher post-MRA plasma renin activity (PRA).

Methods

Single-center retrospective cohort study of adults with PA treated between 2010 and 2025 with ADX or MRA therapy. Follow-up was assessed at =1-month post-therapy. Outcomes were post-therapy PRA (=1.5 vs >1.5 ng/mL/hr, ?PRA), systolic (SBP) and diastolic (DBP) blood pressure, hypokalemia, eGFR, and antihypertensive burden by WHO-defined daily dose (DDD), excluding MRAs. High intensity MRA therapy was defined as spironolactone =100mg/day or eplerenone =200mg/day.

Results

Of 225 patients with PA (median age 56 years; BMI 30.6 kg/m?; 93 (41%) women), 122 (54%) underwent ADX for unilateral PA and 103 (46%) were treated with MRAs. At baseline, ADX group had more severe PA than MRA group: hypokalemia (74 vs 45%; P< 0.001), higher median aldosterone (28.5 vs 17.2 ng/dL; P< 0.001), and higher median DDD (5.0 vs 3.3; P< 0.001).

Post-therapy (median 5 months), no differences in ?PRA (median +0.8 vs +0.8 ng/mL/hr; P=0.163), proportion of patients with PRA>1.5 ng/mL/hr (49 vs 52%; P=0.734), BP reduction (median ?SBP -13.0 vs -13.0 mmHg; P=0.093, ?DBP -5.0 vs -6.5 mmHg; P=0.36), ?eGFR (median -7.0 vs -4.0 mL/min/1.73m?; P=0.296), or hypokalemia (4 vs 11%; P=0.056) were observed between ADX and MRA groups. However, ADX had a greater decline in antihypertensive burden than MRA group (median ?DDD -2.5 vs -1.0; P< 0.001).

In MRA group, patients achieving post-therapy PRA>1.5 ng/mL/hr (n=53) were more likely to be treated with spironolactone (60 vs 36%; P=0.013) and with a higher intensity MRA therapy (38 vs 18%; P=0.03) than those with post-therapy PRA=1.5 ng/mL/hr (n=50).

In multivariable analysis of MRA-treated patients adjusting for age, BMI, baseline DDD and aldosterone, only type of MRA (spironolactone vs eplerenone) was associated with post-treatment PRA>1.5 ng/mL/hr (OR 2.81; P=0.017).

In multivariable analysis of MRA-treated patients adjusting for ?PRA, baseline SBP, aldosterone, age, sex, and BMI, longer duration of hypertension (?=0.04; P=0.04) and lower baseline DDD (?=-0.41; P< 0.001) were associated with lower ?DDD at follow up.

Conclusion

ADX and MRA therapy achieved comparable renin recovery, blood pressure control, and kidney function outcomes, while ADX provided greater reduction in antihypertensive burden. Among MRA-treated patients, agent selection influenced renin response, but renin recovery did not translate into reduced medication requirements. Instead, baseline treatment burden was the dominant factor associated with antihypertensive reduction. These findings support early, aggressive MRA dose titration in non-surgical PA candidates.

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