High rate of detection of primary aldosteronism, including surgically treatable forms, after 'non-selective' screening of hypertensive patients.
BACKGROUND
Wide testing of the aldosterone : renin ratio among hypertensive individuals has revealed primary aldosteronism to be common, with most patients normokalaemic. Some investigators, however, have reported aldosterone-producing adenoma to be rare among patients so detected.


OBJECTIVE
To test the hypothesis that differences among reported studies in the rate of detection of aldosterone-producing adenoma (as opposed to bilateral adrenal hyperplasia) reflect differences in the procedures used for diagnosis of primary aldosteronism, and the methods used to identify aldosterone-producing adenomas.


METHODS
In the newly established Princess Alexandra Hospital Hypertension Unit (PAHHU), we used procedures developed by Greenslopes Hospital Hypertension Unit (which reports that more than 30% of patients with primary aldosteronism have aldosterone-producing adenomas) to diagnose primary aldosteronism and determine the subtype. All patients with an increased aldosterone : renin ratio (measured after correction for hypokalaemia and while the patient was not receiving interfering medications) underwent fludrocortisone suppression testing to confirm or exclude primary aldosteronism; if they were positive, they underwent genetic testing to exclude glucocorticoid-remediable aldosteronism before adrenal venous sampling was used to differentiate lateralizing from bilateral primary aldosteronism.


RESULTS
This approach allowed PAHHU to diagnose, within 2 years, 54 patients [only seven (13%) hypokalaemic] with primary aldosteronism. All tested negative for glucocorticoid-remediable aldosteronism. Aldosterone production was lateralized to one adrenal in 15 patients (31%; only six hypokalaemic) and was bilateral in 34 (69%; all normokalaemic) of 49 patients who underwent adrenal venous sampling. Among patients with lateralizing adrenal hyperplasia, computed tomography revealed an ipsilateral mass in only six and a contralateral lesion in one. Fourteen patients underwent unilateral adrenalectomy, which cured the hypertension in seven and improved it in the remainder. In patients with bilateral primary aldosteronism, hypertension responded to spironolactone (12.5-50 mg/day) or amiloride (2.5-10 mg/day).


CONCLUSIONS
When performed with careful regard to confounding factors, measurement of the aldosterone : renin ratio in all hypertensive individuals, followed by fludrocortisone suppression testing to confirm or exclude primary aldosteronism and adrenal venous sampling to determine the subtype, can result in the detection of significant numbers of patients with specifically treatable or potentially curable hypertension.
Hypertension Unit, University of Queensland Department of Medicine, Princess Alexandra Hospital, Brisbane, Australia. m.stowasser@uq.edu.au
Michael
M
Stowasser
Richard D
RD
Gordon
Thanuja G
TG
Gunasekera
Diane C
DC
Cowley
Gregory
G
Ward
Colin
C
Archibald
B Mark
BM
Smithers
D000236:Adenoma / Q000150:complications / Q000601:surgery; D000310:Adrenal Gland Neoplasms / Q000150:complications / Q000601:surgery; D000311:Adrenal Glands / Q000098:blood supply / Q000378:metabolism / Q000473:pathology; D000315:Adrenalectomy; D000328:Adult; D000368:Aged; D000450:Aldosterone / Q000096:biosynthesis / Q000097:blood / Q000378:metabolism; D005260:Female; D005438:Fludrocortisone; D006801:Humans; D006929:Hyperaldosteronism / Q000150:complications* / Q000175:diagnosis* / Q000209:etiology / Q000601:surgery; D006965:Hyperplasia; D006973:Hypertension / Q000097:blood / Q000150:complications* / Q000188:drug therapy / Q000209:etiology; D008297:Male; D008403:Mass Screening; D008875:Middle Aged; D000451:Mineralocorticoid Receptor Antagonists / Q000627:therapeutic use; D012083:Renin / Q000097:blood; D013148:Spironolactone / Q000627:therapeutic use; D014680:Veins
D000451:Mineralocorticoid Receptor Antagonists; D013148:Spironolactone; D000450:Aldosterone; D012083:Renin; D005438:Fludrocortisone