Are women more at risk of false-positive primary aldosteronism screening and unnecessary suppression testing than men?
BACKGROUND
Because primary aldosteronism is not uncommon, specifically treatable and in some cases curable, and carries higher risks for cardiovascular morbidity and mortality than essential hypertension, screening hypertensive patients for its presence by measuring aldosterone to renin ratio (ARR) is increasingly common. A significantly higher false-positive ARR rate for women than men, resulting in unnecessary suppression tests has previously been reported.


METHODS
Using a new, highly accurate aldosterone assay and both of the currently widely used renin assays, ARR was measured in 19 normal, ovulating women at three time points in the menstrual cycle and compared with single measurements in 21 normal males of similar age.


RESULTS
ARRs in males were possibly too well down in the current normal range. Although normotensive and normokalemic, two women had raised ARRs in the luteal phase but only when direct renin concentration (DRC) was used. Their DRC levels were low at all sampling times [despite midrange plasma renin activity levels], whereas their progesterone and aldosterone levels were highest for the group. Saline suppression testing, performed in one of them, showed normal aldosterone suppressibility.


CONCLUSIONS
False-positive ARRs in normal women during the luteal phase only when DRC is used may explain the higher incidence of false-positive ARRs in hypertensive women than men and suggest the following: 1) plasma renin activity is preferable to DRC in determination of ARR and 2) new reference ranges for ARR that take into account gender and sex hormone levels are required.
Ahmed
Ashraf H
AH
Endocrine Hypertension Research Centre, University of Queensland School of Medicine, Princess Alexandra Hospital, Ipswich Road, Woolloongabba, Brisbane 4102, Australia.
Gordon
Richard D
RD
Taylor
Paul J
PJ
Ward
Gregory
G
Pimenta
Eduardo
E
Stowasser
Michael
M
D000328:Adult; D000450:Aldosterone / Q000097:blood; D002851:Chromatography, High Pressure Liquid; D005189:False Positive Reactions; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D006929:Hyperaldosteronism / Q000175:diagnosis*; D007118:Immunoassay; D008297:Male; D008597:Menstrual Cycle / Q000378:metabolism; D000451:Mineralocorticoid Receptor Antagonists; D011374:Progesterone / Q000097:blood; D012083:Renin / Q000097:blood; D012727:Sex Characteristics; D053719:Tandem Mass Spectrometry
D000451:Mineralocorticoid Receptor Antagonists; D000450:Aldosterone; D011374:Progesterone; D005640:Follicle Stimulating Hormone; D012083:Renin; D006854:Hydrocortisone