The role of supine position in obstructive sleep apnea in patients with stroke: A cross-sectional study comparing stroke unit patients with outpatients.

Obstructive sleep apnea (OSA) presents an elevated risk to patients with stroke, especially during the acute phase when prolonged bed rest in the supine position is common in stroke unit (SU). Recent studies suggest that rostral fluid shifts may worsen OSA severity. This study aimed to compare OSA severity between patients with acute stroke in a SU and outpatients with OSA using in-laboratory polysomnography (iPSG) to gain further insight into this relationship. This cross-sectional study was conducted at Samsung Changwon Hospital between April 2021 and October 2022. Patients with acute stroke and outpatients who underwent iPSG were included. SU patients were screened for OSA symptoms and selected based on modified Mallampati score ≥ 3. SU patients were assessed using iPSG during their hospital stay after bed rest periods. Propensity score matching (PSM) was used to control for confounding variables. Among 530 SU patients, 30 completed iPSG. SU patients exhibited significantly higher supine apnea-hypopnea index (AHI) than outpatients (60.1 vs 28.4, P = .004). The stroke group showed increased odds of elevated supine AHI (OR = 4.99, 95% CI: 1.90-13.11, P = .001). After PSM adjustment, the association remained significant (OR = 18.47, 95% CI: 1.53-222.20, P = .022). Eighty percent of SU patients had moderate-to-severe OSA (AHI ≥ 15) compared to 60% of outpatients. Patients with acute stroke in a SU demonstrate significantly higher supine AHI compared to outpatients with OSA. These findings suggest that prolonged bed rest and supine positioning during acute stroke management may contribute to OSA severity.