Patients at high risk for OSA were almost two times more likely to have primary hyperaldosteronism (36% versus 19%, P < 0.05) with low plasma renin activity (1.2 ± 1.8 ng/mL/hr versus 1.9 ± 4.1 ng/mL/hr) and significantly greater 24 hr urinary aldosterone excretion (13.6 ± 9.6 mcg versus 9.8 ± 7.6 mcg, P < 0.05) compared to subjects at low risk of OSA, suggesting an association between primary hyperaldosteronism and OSA [27]. Here, REN is linked to obstructive sleep apnea syndrome.