Effect of Combined Hormonal Replacement Therapy on the Aldosterone/Renin Ratio in Postmenopausal Women.  

Presentation Number: SUN 521
Date of Presentation: April 2nd, 2017

Ashraf H Ahmed*1, Richard Gordon2, Greg Ward3, Martin Wolley4, Brett McWhinney5, Jacobus P Ungerer6 and Michael Stowasser7
1University of Queensland, 2University of Queensland, Brisbane, Australia, 3Sullivan & Nicolaides Pathology, Brisbane, Australia, 4University of Queensland School of Medicine, Brisbane, Australia, 5Royal Brisbane and Women's Hospital, Herston, Australia, 6Pathology Queensland, Queensland Health, 7University of Queensland School of Medicine, Greenslopes and Princess Alexandra Hospitals, Brisbane, Australia

Abstract

Background: Plasma aldosterone/renin ratio (ARR) is the most popular screening test for primary aldosteronism (PA). Because both estrogen and progesterone affect aldosterone and renin levels, we studied effects of combined hormonal replacement therapy (HRT) on ARR, measuring renin as both direct renin concentration (DRC) and plasma renin activity (PRA).

Methods: 15 normotensive, healthy postmenopausal women underwent measurement (seated, midmorning) of plasma aldosterone, DRC, PRA, electrolytes and creatinine and urinary aldosterone, cortisol, electrolytes and creatinine at baseline and after 2 weeks and six weeks treatment with combined HRT (conjugated oestrogens 0.625 mg and medroxyprogesterone 2.5 mg daily).

Results: Treatment with combined HRT was associated with significant increases in aldosterone [baseline median (range) 150 (85-600), 2 weeks 230 (129-790), 6 weeks 434 (200-1200) pmol/L; P<0.001 (Friedman Test)] and PRA [2.3 (1.2-4.3), 3.8 (1.4-7.0), 5.1 (1.4-10.8) ng/mL/h; P<0.001]; but decreases in DRC [21 (10-31), 21 (10-39), 14 (8.0-30) mU/L; P<0.01] leading to increases in ARR calculated by DRC [7.8 (3.6-34.8), 11.4 (5.4-48.5), 30.4 (10.5-90.2); P<0.001]. The ARR calculated by DRC exceeded the cut off value (70) in three patients after 6 weeks. There were no significant changes in ARR calculated by PRA [79 (26-184), 91 (23-166), 88 (50-230); P=0.282], plasma electrolytes and creatinine, and all urinary measurements.

Conclusion: The combined oral HRT used in this study is capable of significantly increasing ARR with a risk of false positive results during screening for PA, but only if DRC (and not PRA) is used to calculate the ratio

 

Nothing to Disclose: AHA, RG, GW, MW, BM, JPU, MS