Changes of aldosterone levels in patients with type 2 diabetes complicated by moderate to severe obstructive sleep apnea–hypopnea syndrome before and after treatment with continuous positive airway pressure

Objective Both obstructive sleep apnea–hypopnea syndrome (OSAHS) and type 2 diabetes mellitus (T2DM) are closely related to the renin-angiotensin-aldosterone system. We investigated whether hyperaldosteronemia is found in patients with OSAHS complicated by T2DM and whether continuous positive airway pressure (CPAP) treatment can significantly reduce the aldosterone level. Methods Patients with T2DM were classified into an OSAHS group [apnea–hypopnea index (AHI) of ≥15] and a control group (without OSAHS; AHI of <5). The OSAHS group was exposed to CPAP for 7 days (7 h/day). Results The plasma aldosterone, plasma renin, and urinary aldosterone levels were higher in the OSAHS than control group. The plasma aldosterone and renin levels were significantly lower after than before treatment in the OSAHS group, but they were still higher than the baseline levels in the control group. The post-treatment urinary aldosterone level was significantly higher in the OSAHS than control group. No correlation was found between the AHI and plasma renin, plasma aldosterone, and 24-hour urinary aldosterone levels. The blood glucose level in the OSAHS group did not significantly change after treatment. Conclusions The plasma and urine aldosterone levels are increased in patients with concurrent T2DM and OSAHS and are significantly reduced by CPAP. Trial registration: ChiCTR-ION-16009837