Table 2.

Group comparison according to polysomnographic parameters

	Control (n = 61)	Mild OSAS (n = 67)	Moderate OSAS (n = 61)	Severe OSAS (n = 101)	ANOVA p
AHI	1.91 ± 1.69	9.14 ± 3.03^*	21.5 ± 4.98^*,+	72.5 ± 51.7^*,+	<0.001
Sleep efficiency, %	81.0 ± 9.14	81.0 ± 9.91	82.0 ± 10.3	77.1 ± 13.1^*	0.026
Total sleep time, min	322.8 ± 44.8	298.7 ± 60.4	292.2 ± 62.4	257.0 ± 78.2^*	<0.001
Stage 1, min	58.2 ± 32.0	39.5 ± 37.9	48.2 ± 53.7	73.5 ± 59.8^*	0.006
Stage 2, min	139.6 ± 71.8	103.2 ± 67.3	125.7 ± 69.6	70.9 ± 43.30^*	<0.001
Baseline SaO₂, %	97.3 ± 0.96	95.5 ± 1.77	93.9 ± 3.07	92.0 ± 4.87^*	<0.001
Lowest SaO_2, %	91.3 ± 3.09	88.4 ± 3.82	81.3 ± 8.68^*	79.0 ± 8.87^*	<0.001
ESS	8.7 ± 4.6	8.9 ± 5.2	10.4 ± 5.9	11.6 ± 6.0^*	0.029

AHI: apnea-hypopnea index; ESS: Epworth sleepiness scale

*p < 0.05 vs. control group, +p < 0.05 vs. mild OSAS group