Objective: To study the value of a new measurement that divided obstructive sleep apnea-hypopnea syndrome (OSAHS) into rapid-eye-movement (REM) related and non-rapid-eye-movement (NREM) related subgroups.
Methods: According to Siddiqui classification, 137 adult patients with OSHAS were diagnosed as REM-related OSAHS [REM apnea hypopnea index (AHI)/NREM AHI > 1] or NREM-related OSAHS (REM AHI/NREM AHI < 1). Polysomnographic data were compared and discussed.
Results: (1) There were 72 cases defined as REM-related OSAHS (52.6%) and 65 cases defined as NREM-related OSAHS (47.4%). (2) In all cases, total AHI and NREM AHI in REM-related OSAHS were significantly lower than those in NREM-related OSAHS, while lowest arterial oxygen saturation (LSaO₂), REM LSaO₂ and NREM LSaO₂ were significantly higher than those in NREM-related OSAHS (t were -6.466, -7.638, 3.426, 2.472, 4.873 respectively, P < 0.05). No significance was found in sleep structure, REM AHI and REM LSaO₂ between REM-related and NREM-related OSAHS (P > 0.05). (3) Given the severity of OSHAS, the constituent ratio of REM-related OSAHS decreased (77.8%, 61.5%, 37.3%) from mild to severe OSAHS, while that of NREM-related OSAHS rose (22.7%, 38.5%, 62.7%; chi² = 16.996, P < 0.01). In mild and moderate groups, REM LSaO₂ of REM-related OSAHS was significantly lower than those in NREM-related OSAHS (t were -4.273 and -2.136, P < 0.05), while the differences of total AHI and LSaO₂, NREM LSaO₂ between these two types were not significant. In severe group, AHI in NREM-related OSAHS was significantly higher than that in REM-related OSAHS, while LSaO₂, REM LSaO₂ and NREM LSaO₂ was significantly lower than those in REM-related OASHS (t were -4.943, 2.574, 1.996, 3.571, P ≤ 0.05). (4) There was no significance in sleeping latency and efficiency between REM-related and NREM-related OSHAS.
Conclusions: REM-related OSHAS mainly exists in mild and moderate OSHAS, while NREM-related one mainly exists in severe OSHAS. NREM-related OSAHS may be more severe in AHI and hypoxia than REM-related one. Whenever obstructive apnea happened in REM or NREM period, its impacts on sleep structure, efficiency and latency have no difference.