Primary Hyperaldosteronism Not as Common as Previously Thought

By Todd Neale
THESSALONIKI, 08 june 2008-- Primary hyperaldosteronism, thought to be prevalent in patients with resistant hypertension, is not as common in hypertensive patients as previous studies have suggested, researchers found.Of 1,616 patients with resistant hypertension, 11.3% had confirmed primary hyperaldosteronism, Michael Doumas, M.D., of Hippokration Hospital here, and colleagues reported in the June 7 issue of The Lancet."If we take into account that resistant hypertension is seen in 10% to 30% of people with hypertension and primary hyperaldosteronism is less prevalent in milder forms of hypertension," the researchers said, "we could rationally assume that primary hyperaldosteronism is substantially less common in patients with hypertension than currently thought."
To test that assumption, Dr. Doumas and colleagues did a retrospective analysis of 1,616 patients (mean age 55.8; 51% male) with resistant hypertension -- a blood pressure greater than 140/90 mm Hg that did not respond to a three-drug treatment including a diuretic -- who were evaluated at a clinic in Thessaloniki over 20 years.
Serum aldosterone and plasma renin activity were measured in all patients and the ratio of the two was calculated to screen for primary hyperaldosteronism.
Patients with a ratio greater than 65.16 and a serum aldosterone level of 416 pmol/L or higher -- 338 or 20.9% of the study population -- were considered positive, although further testing was required to verify the diagnosis.
These patients underwent two salt suppression tests, which identified 182 (11.3% of the total patient population) who had primary hyperaldosteronism.
Treatment with spironolactone -- an aldosterone receptor blocker -- significantly lowered the blood pressure in all 182 patients (P<0.0001), href="http://www.thelancet.com/journals/lancet/article/PIIS014067360860834X/abstract" target="_blank">"Prevalence of primary hyperaldosteronism in resistant hypertension: a retrospective observational study" Lancet 2008; 371: 1921-1926. Additional source: The LancetSource reference: Kaplan N, "Déjà vu for primary aldosteronism" Lancet 2008; 371: 1890-1891.