Continuous positive airway pressure improves nocturnal polyuria in ischemic stroke patients with obstructive sleep apnea

OBJECTIVES: To assess the effect of continuous positive airway pressure (CPAP) on nocturia in ischemic stroke patients with obstructive sleep apnea (OSA). METHODS: This was a prospective and non-randomized controlled study in which ischemic stroke patients with OSA being treated in a rehabilitation ward were enrolled. The participants who tolerated CPAP were classified as the CPAP group, while those who refused or could not tolerate CPAP were classified as the control group. The percentage change of nocturia before and after 2 weeks of CPAP therapy between the two groups were compared. RESULTS: A total of 44 participants were enrolled in and 35 participants (mean age= 59.8±11.7 years old; mean apnea hypopnea index=42.9±16.7/h) completed the study (control group: 14, CPAP group: 21). Overall, 69% of the participants had nocturnal polyuria and 69% of them had more than one nocturia episode per night. The baseline and initial nocturia characteristics did not differ significantly between the two groups. As compared to the control group, CPAP therapy significantly decreased the nocturnal polyuria index (mean percentage change: 9% vs −21% (P=0.005)) and nocturnal urine output (mean percentage change: 6% vs −26% (P=0.04)), but not the nocturia episodes or 24-hours total urine output. CONCLUSION: Nocturia due to nocturnal polyuria is very common in post-stroke patients with OSA. Treating OSA by CPAP significantly reduces nocturnal polyuria, but not nocturia frequency, in ischemic stroke patients.