Impact of Sleep Fragmentation and Arousal on Nonalcoholic Fatty Liver Disease in Patients with Obstructive Sleep Apnea: A Cross-Sectional Study

Purpose: Obstructive sleep apnea (OSA) is a contributing factor to nonalcoholic fatty liver disease (NAFLD). This study aimed to investigate the clinical and polysomnographic characteristics of OSA patients with and without NAFLD, focusing on the relationships between sleep fragmentation, arousal and NAFLD. Materials and Methods: We consecutively enrolled patients who underwent polysomnography, anthropometry, blood sampling, and abdominal ultrasonography. Patients were categorized into NAFLD and non-NAFLD groups. A comparative analysis of clinical and polysomnographic profiles was conducted, followed by multivariate binary logistic regression to explore the relationship between sleep disturbance indices and NAFLD. Results: A total of 403 subjects were included, including 92 patients with NAFLD and 311 with non-NAFLD. NAFLD patients exhibited a greater apnea-hypopnea index (AHI) (51.19/h vs 33.60/h, p = 0.002) and oxygen desaturation index (ODI) (37.90/h vs 21.40/h, p=0.034) compared to non-NAFLD patients. Specifically, NAFLD patients had a higher rapid eye movement (REM)-AHI (53.70/h vs 43.60/h, p=0.001) and greater arousal index (AI) (32 vs 25, p = 0.009). Additionally, sleep latency (SL) was significantly lower in the NAFLD group (p < 0.05). Multivariate logistic regression analysis confirmed that REM-AHI (OR=1.023, p = 0.024), AI (OR=1.140, p = 0.01), and SL (OR=0.956, p = 0.035) were significantly associated with NAFLD in OSA patients. Conclusion: This study revealed that sleep disturbance indices, especially AI, REM-AHI and SL, were closely related to NAFLD. When evaluating whether OSA patients are complicated with NAFLD, more attention should be given to sleep fragmentation and arousal.