Independent variables

Adjusted odds ratio

95% confidence interval

P value

Age ≥ 75 years

3.41

1.31 - 8.87

0.012

Male sex

2.21

0.71 - 6.94

0.173

Body mass index ≥ 25 kg/m²

2.61

1.07 - 6.40

0.036

Mallampati classification III or IV

0.66

0.28 - 1.58

0.349