THU599 Serum And Urinary Free Cortisone As Novel Predictor Of Low-renin Arterial Hypertension

Disclosure: A. Tapia-Castillo: None. J. Perez: None. A. Sandoval: None. F. Allende: None. S. Solari: None. C.E. Fardella: None. C. Carvajal: None. A large proportion of low-renin hypertensive (LRH) patients correspond to primary aldosteronism (PA) caused by excessive MR activation mediated by excess of aldosterone. However, some of these LRH patients have low to normal serum aldosterone levels, where is thought the MR activation is aldosterone-independent and more likely due to glucocorticoid-mediated MR activation, as occurs in the nonclassical apparent mineralocorticoid excess (NCAME), which is characterized by high cortisol/cortisone ratio and low cortisone, affecting not only blood pressure (BP) control and urinary potassium excretion but also causing cardiac and renal damage, endothelial dysfunction and subclinical inflammation. Objective: To evaluate cortisone as a predictor of LRH and its association with parameters of kidney and vascular damage. Design: A cross-sectional study was carried out in 206 adult subjects. The subjects were classified according to low-renin phenotype (plasma renin activity (PRA) <1ng/ml*h) and low serum cortisone (<p25th). We measured clinical, biochemical, renal and vascular parameters. Statistical analyses as group comparisons were performed by Mann Whitney, and discriminatory analyses by ROC curves. Results: We identified 43% of subjects with low-renin phenotype. PRA was associated with serum aldosterone (r=0.36; p<0.001) and serum cortisone (r=0.22; p=0.001). A binary logistic regression analysis shows that cortisone predicts low-renin phenotype (OR=0.4 [95% CI, 0.21 – 0.78]). The ROC curves show an AUC for serum cortisone was 0.62 (95% CI: 0.54 to 0.69; p = 0.004) and urinary cortisone 0.6 (95% CI: 0.52 to 0.67; p = 0.02) to discriminate subjects with low-renin from controls. Subjects with low serum cortisone showed a higher albuminuria, PAI-1 and lower sodium renal excretion. Urinary free cortisone was also associated to blood pressure and serum potassium (p<0.05). Conclusion: These findings highlight the concept that the low-renin phenotype is dictated not only by serum aldosterone levels but also by low cortisone, suggesting it should be considered in endocrine arterial hypertension screening, complementary in the diagnosis of primary aldosteronism since it could generate false positives in the calculation of the aldosterone to renin ratio. Moreover, our study suggests that low cortisone levels could be associated with future occurrence of vascular and kidney damage. Presentation: Thursday, June 15, 2023