Elevated renin activity and change in sleep apnea with primary aldosteronism

Background: The prevalence of obstructive sleep apnea (OSA) is higher in patients with primary aldosteronism (PA), while elevated renin activity after treatment is associated with a lower risk of cardiovascular events. However, the association of PA with degree of OSA remains unclear and it is not known whether elevated renin activity in PA patients is associated with change in apnea condition. Methods: Cross-sectional relationships between PA (n=176) and degree of OSA classified by apnea-hypopnea index (AHI) with use of an apnomonitor were investigated, with the results compared with those obtained with non-PA patients (n=418). Additionally, the effects of elevated renin activity on change in AHI were prospectively examined in 45 patients with PA. Results: Patients with PA were found to be significantly associated with severe OSA even after adjustment for other clinical risk factors (odds ratio 2.08, 95% confidence interval 1.09-3.95, p = 0.025) as compared to those without PA. Furthermore, the logarithm of the renin activity after treatment and change in AHI before and after treatment were significantly negatively correlated, with Pearson's correlation coefficient (r = -0.364, p = 0.014). Conclusions: Severe OSA is more commonly seen in PA patients with hypertension as compared to patients without PA, and elevated renin activity may contribute to improvement of sleep apnea in patients with PA.