Preliminary study on clinical characteristics of Chinese patients with positional obstructive sleep apnea

Purpose The objective of this study was to evaluate the prevalence, the clinical characteristics, and the possible predictors of Chinese patients with positional obstructive sleep apnea (POSA) according to the Amsterdam Positional Obstructive Sleep Apnea Classification (APOC). Methods A retrospective study in the sleep unit of Peking Union Medical College Hospital was conducted to analyze the clinical and polysomnography data of Chinese patients with obstructive sleep apnea (OSA). Results Of 372 patients with OSA, 54% met the APOC criteria for POSA. The prevalence of POSA was significantly higher in women with OSA than in men. Chinese patients with POSA had a lower apnea–hypopnea index, oxygen desaturation index, and the percentage of time spent at oxygen saturation below 90% in total sleep time; and a higher mean oxygen saturation (SaO 2 ) and minimum SaO 2 during sleep, which were remarkable in the APOC I group. By multivariate logistic regression analyses, the higher mean SaO 2 (≥95%) during sleep and mild and moderate OSA were positive predictors of POSA. Mild and moderate OSA was the independent predictor of POSA in women. Higher mean SaO 2 (≥95%) during sleep was the independent predictor of POSA in men. Conclusion According to the APOC, the prevalence of POSA is high in Chinese patients with OSA, especially in women. Chinese patients with POSA had less severe OSA and a lower degree of nocturnal hypoxia, which was remarkable in the APOC I group.