Positive relationship of sleep apnea to hyperaldosteronism in an ethnically diverse population.

Objective: Approximately, 50-60% of patients with sleep apnea have hypertension. To explore a mechanism of this relationship, we compared its prevalence in a hypertensive population with and without hyperaldosteronism.

Methods: Using the Kaiser Permanente Southern California database, hypertensive individuals who had plasma aldosterone and plasma renin activity measured between 1 January 2006 and 31 December 2007 were evaluated. Hyperaldosteronism was defined as an aldosterone : renin ratio more than 30 and plasma aldosterone more than 20 ng/dl or an aldosterone : renin ratio more than 50 (ng/dl : ng/ml per h). Hypertension was identified by International Classification of Disease, Ninth Revision (ICD-9) coding and sleep apnea was defined by ICD-9 coding or procedural coding for dispensation of positive airway devices.

Results: Of 3428 hypertensive patients, 575 (17%) had hyperaldosteronism. Sleep apnea was present in 18% (105) with hyperaldosteronism vs. 9% (251) without hyperaldosteronism (P < 0.001). Odds ratio for sleep apnea in patients with hyperaldosteronism was 1.8 (95% confidence interval 1.3-2.6) after controlling for other sleep apnea risk factors. No ethnic group was at greater risk for sleep apnea.

Conclusion: The prevalence of sleep apnea in a diverse hypertensive population is increased in patients with hyperaldosteronism, even when controlling for other sleep apnea risk factors.