Table 3 Independent predictors of hypoxia on multivariable and univariable regression analysis in full analysis set.

Variables	Univariable model		Multivariable model
	OR (95%CI)	P value	OR (95%CI)	P value
ASA, American Society of Anesthesiologists; BMI, body mass index; CI, confidence interval; OR, odds ratio; SpO 2 , pulse oxygen saturation.
Sex
Male	1 (ref)		1 (ref)
Female	1.37 (1.07–1.76)	0.013	1.65 (1.25–2.18)	< 0.001
Age	1.03 (0.99–1.06)	0.16	1.04 (1.00–1.08)	0.050
BMI (kg/m 2 )	1.14 (1.10–1.19)	< 0.001	1.12 (1.07–1.17)	< 0.001
ASA physical status
1	1 (ref)		1 (ref)
2	0.91 (0.62–1.34)	0.628	0.79 (0.51–1.22)	0.286
Procedure type
Gastroscopy	1 (ref)		1 (ref)
Colonoscopy	0.42 (0.27–0.67)	< 0.001	0.38 (0.24–0.61)	< 0.001
Gastrointestinal Endoscopy	1.41 (1.06–1.88)	0.019	1.41 (0.98–2.01)	0.063
Initial propofol (mg)	1.02 (1.01–1.02)	< 0.001	1.02 (1.01–1.02)	< 0.001
Mallampati classification
1	1 (ref)		1 (ref)
2	1.52 (1.13–2.03)	0.005	1.21 (0.88–1.67)	0.241
3	1.78 (1.26–2.51)	0.001	1.38 (0.93–2.05)	0.111
4	1.88 (0.93–3.80)	0.081	1.30 (0.59–2.89)	0.515
Snore
No	1 (ref)		1 (ref)
Yes	1.84 (1.44–2.37)	< 0.001	1.51 (1.13–2.02)	0.005
Pre-anesthesia SpO 2 (%)	0.73 (0.67–0.80)	< 0.001	0.73 (0.66–0.81)	< 0.001