Association between minimum nocturnal heart rate and cerebral small vessel disease in patients with obstructive sleep apnea.

INTRODUCTION

Obstructive sleep apnea (OSA) has been implicated in cerebral small vessel disease (CSVD) through mechanisms involving intermittent hypoxia, autonomic imbalance, and metabolic dysregulation, but the pathways remain insufficiently elucidated. This retrospective observational study sought to identify clinical and physiological factors associated with CSVD in adults with OSA.

METHODS

We reviewed adult patients who underwent overnight polysomnography and were diagnosed with OSA at the Sleep Medicine Department of the People's Hospital of Guangxi Zhuang Autonomous Region from January 2021 to December 2023. Data collected included demographics, polysomnography, biochemical markers, and brain MRI. The primary outcome was the presence of CSVD. Multivariate logistic regression determined independent factors, and model discrimination was assessed with the area under the receiver operating characteristic curve (AUC).

RESULTS

Among 630 patients, 265 (42%) had CSVD. Compared with those without CSVD, patients with CSVD had shorter NREM sleep latency, more nocturnal awakenings, and a distinct lipid profile with lower LDL-C and ApoB, but higher HDL-C and ApoA1/B ratios. Multivariate analysis identified older age (OR 1.095, 95% CI 1.071-1.118, p < 0.001) and higher nocturnal minimum heart rate (OR 1.023, 95% CI 1.006-1.040, p = 0.008) as independently associated with CSVD. The model showed good discrimination (AUC 0.752).

DISCUSSION: Elevated nocturnal minimum heart rate, possibly reflecting altered autonomic regulation, was independently associated with CSVD in OSA. Findings suggest autonomic dysfunction and sleep fragmentation may contribute to CSVD pathogenesis in this population.