Autonomic responses to respiratory events and risk of chronic kidney disease in obstructive sleep apnea.

Study objectives: Obstructive sleep apnea (OSA)-related hypoxemia, measured by hypoxic burden (HB), is associated with chronic kidney disease (CKD). OSA-related autonomic response may also be associated with CKD. This study examined whether individuals with high HB and varying autonomic responses to OSA have a different risk of CKD progression compared to those with low HB.

Methods: Polysomnography data from the multi-centre Canadian Sleep and Circadian Network cohort were analyzed. HB was defined as the area under event-related oxygen desaturation curves during sleep. Autonomic responses were assessed using "vasoconstriction burden" (VCB: area under photoplethysmography declines, reflecting vascular reactivity) and heart rate response to events (ΔHR, reflecting cardiac autonomic response). Estimated glomerular filtration rate and urine albumin:creatinine ratio were used to identify participants at risk of CKD progression. This risk was compared across individuals with high HB(≥median) and varying levels of autonomic responses relative to those with low HB.

Results: Data from 421 participants were analyzed. The odds of CKD progression was higher in those with high vs low HB. Compared to the low HB group, individuals with high HB and low VCB (lowest quartile) were at increased risk of CKD progression (odds ratio [95% CI] = 2.49 [1.23,5.05]), whereas the risk was not significantly elevated in those with the high VCB (highest quartile). In contrast, within high HB, both high (highest quartile) and low ΔHR (lowest quartile) groups were at increased risk of CKD progression compared to those with low HB.

Conclusions: Autonomic response to respiratory events improves risk stratification for CKD progression in OSA. VCB and ΔHR show distinct associations with this risk.