BACKGROUND:
Renin suppression in primary aldosteronism indicates mineralocorticoid receptor activation via excessive aldosterone secretion, inducing renal damage. We investigated whether the reversal of renin suppression after the initiation of mineralocorticoid receptor antagonist therapy was associated with long-term renal outcomes in medically treated patients with primary aldosteronism.

METHODS:
This retrospective cohort study included 318 patients with primary aldosteronism treated with mineralocorticoid receptor antagonist between 2008 and 2020 at the Yokohama Rosai Hospital in Japan. The posttreatment renin status was defined as unsuppressed (ie, reversal of renin suppression) when individual plasma renin activity after the initiation of mineralocorticoid receptor antagonist (post-plasma renin activity) was ≥1.0 ng/mL per hour; otherwise, it was defined as suppressed. We analyzed the association of posttreatment renin status with subsequent longitudinal estimated glomerular filtration rate changes using linear mixed-effects models for repeated measurements, adjusting for potential confounders.

RESULTS:
The posttreatment renin status of 119 patients was unsuppressed (median post-plasma renin activity, 1.7 ng/mL per hour) and that of 199 patients was suppressed (median post-PRA, 0.5 ng/mL per hour). Through the median follow-up period of 3.1 years, the decline in estimated glomerular filtration rate was milder among patients with the unsuppressed posttreatment renin (−0.46 [95% CI, −0.63 to −0.28] mL/min per 1.73 m2 per year) than those with suppressed posttreatment renin (−1.41 [95% CI, −1.56 to −1.27] mL/min per 1.73 m2 per year; difference, 0.96 [95% CI, 0.72–1.20] mL/min per 1.73 m2 per year).

CONCLUSIONS:
Our findings may highlight the importance of reversing renin suppression with optimal mineralocorticoid receptor antagonist titration in medically treated primary aldosteronism, which could mitigate adverse renal outcomes.