NEW YORK — A link between aldosterone, hypertension, and obstructive sleep apnea was made in a study with 71 patients.
“We found an extraordinarily high prevalence of obstructive sleep apnea in patients with [treatment-] resistant hypertension,” and serum aldosterone levels were significantly related to the severity of sleep apnea,” Dr. David A. Calhoun said at the annual meeting of the American Society of Hypertension. “We went in thinking that obstructive sleep apnea was driving aldosterone release, but now we think that a high serum level of aldosterone somehow contributes to worsening sleep apnea,” said Dr. Calhoun, a hypertension specialist at the University of Alabama, Birmingham.
The link may be mediated by increased salt and water retention or perhaps by a change in flow resistance.
Dr. Calhoun and his associates have begun a study to explore the implications of their findings for patient management. They are withholding continuous positive air pressure, a standard treatment for obstructive sleep apnea, from patients with the disorder and are instead treating them with spironolactone, an aldosterone antagonist. The goal is to see whether spironolactone alone is effective at relieving sleep apnea.
The current study involved a consecutive series of 41 men and 30 women who were referred to the hypertension clinic at UAB because of treatment-resistant hypertension. Their mean blood pressure was 156/88 mm Hg despite treatment with an average of four antihypertensive drugs.
The patients were assessed for obstructive sleep apnea by diagnostic polysomnography. The overall prevalence of obstructive sleep apnea was 85%, with a prevalence of 90% in the men and 79% in the women. The average apnea-hypopnea index for all patients was 24 apnea events per hour.
The patients with sleep apnea also had high serum and urine levels of aldosterone. Those with the most severe sleep apnea had the highest levels, Dr. Calhoun said.
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