Table 2.

Description of and labels for the polysomnographic clusters based on distinguishing features

Cluster (n)	Cluster label	Median AHI* (events/hour)	Conventional OSA severity*
A (533)	Mild	4	None/mild
B (119)	PLMS	10
C (186)	NREM and poor sleep	19	Moderate
D (168)	REM and hypoxia	19
E (75)	Hypopnoea and hypoxia	44	Severe
F (42)	Arousal and poor sleep	68
G (124)	Combined severe	84

^*OSA severity definitions: none/mild (AHI <15), moderate (15≤ AHI<30) and severe (AHI ≥30). AHI was not used in generating patient clusters. Median AHIs and severity categories based on median AHI for each cluster are shown for descriptive purposes only (mean AHIs were 7.5, 13.6, 24.0, 25.0, 47.6, 72.6 and 82.4 for clusters A, B, C, D, E, F and G, respectively).

AHI, apnoea–hypopnoea index; NREM, non-rapid eye movement; OSA, obstructive sleep apnoea; PLMS, periodic limb movements of sleep; REM, rapid eye movement.