Effect of fluid balance control on obstructive sleep apnea in peritoneal dialysis patients with volume overload: A pre- and post-intervention study

<bold>Background:</bold> Obstructive sleep apnea (OSA) is highly prevalent in peritoneal dialysis (PD) patients. Fluid overload and upper airway edema are suspected contributors, but the impact of fluid balance control on sleep apnea remains unexplored. <bold>Methods:</bold> We enrolled 14 PD patients with severe OSA. A fluid balance intervention targeting to maintain actual body weight within 1.5 kg of estimated dry weight was implemented. The primary outcome was change in apnea-hypopnea index (AHI) assessed by polysomnography. <bold>Results:</bold> Ten patients achieved successful fluid balance control. In this group, median AHI significantly decreased from 64.2 events/hr [IQR: 52.3-75.6] to 34.8 events/hr [IQR: 26.9-47.3] (p=0.005), accompanied by a reduction in median overhydration fluid from 2.7L [IQR: 1.8-3.1] to 1.3L [IQR: 1.2-1.6]. Significant improvements in nocturnal hypoxemia, overnight neck diameter changes and NT-proBNP levels were also observed. Notably, overnight ultrafiltration volumes remained stable around 1000ml [800-1,387.5] in this group. Four patients did not achieve fluid balance goals, and their AHI remained virtually unchanged (55.2 [IQR 47.4-65.8] vs. 53.7 [47.6-62.4]). Additionally, their median overhydration fluid remained elevated at 2.8L [IQR: 2.5-3.1]. No serious adverse events were reported. <bold>Conclusion:</bold> This is the first study to demonstrate that fluid balance intervention targeting to maintain actual body weight within 1.5 kg of estimated dry weight significantly improves OSA severity in PD patients and shows promise as a potential therapeutic strategy.