Relationship between metabolic syndrome and hypercapnia among obese patients with sleep apnea

Table 2 Sleep study data

	OSA without hypercapnia (n = 72)	OSA with hypercapnia (n = 25)	P value
TST, min	333.5 ± 82.7	330.6 ± 69.7	0.876
Total AHI, events/h	60.8 ± 20.5	65.6 ± 26.1	0.353
Obstructive	58.0 ± 21.9	64.8 ± 26.6	0.206
Central	0.3 (0.9)	0.3 (0.6)	0.815
Time spent SO2< 90%/TST, %	46.1 (54.7)	56.9 (60.0)	0.128
Lowest SO2, %	69.5 ± 9.2	68.8 ± 7.8	0.764
Arousal index, events/h	55.2 ± 24.1	59.1 ± 25.1	0.491
Sleep stages, %TST
N1	40.5 ± 16.7	45.2 ± 18.7	0.245
N2	44.8 ± 13.2	39.4 ± 15.1	0.094
N3	2.3 (9.0)	6.1 (9.7)	0.817
REM	9.1 (6.2)	10.8 (5.7)	0.494

AHI: Apnea-hypopnea index; OSA: Obstructive sleep apnea; REM: Rapid eye movement; SO₂: Oxyhemoglobin saturation; TST: Total sleep time.