Table 4– Factors significantly different between obstructive sleep apnoea (OSA) and non-OSA cases

Factor	Source	Type	Subjects n	Statistical test	p-value
Body mass index	SDB-Q	Continuous	158	Mann–Whitney U-test	0.013
Difficulty breathing when asleep	SDB-Q	Categorical	176	Chi-squared test	0.074
Snoring loudness	SDB-Q	Categorical	166	Chi-squared test	0.007
OSA score	SDB-Q	Continuous	183	Mann–Whitney U-test	0.060
Doctor-diagnosed allergy/chronic rhinitis	HPO-Q	Categorical	172	Chi-squared test	0.065
Weighted cumulative hypoxia index	HPO	Continuous	167	Mann–Whitney U-test	0.088
Index of desaturation events of ≥4% S_p,O₂	HPO	Continuous	167	Mann–Whitney U-test	0.007
Index of desaturation event clusters	HPO	Continuous	167	Mann-Whitney U-test	<0.001
Index of desaturation events to ≤92% S_p,O₂	HPO	Continuous	167	Mann–Whitney U-test	0.002
Index of desaturation events to ≤90% S_p,O₂	HPO	Continuous	167	Mann–Whitney U-test	<0.001
Nadir S_p,O₂	HPO	Continuous	167	Mann–Whitney U-test	0.002
≥3 desaturation events to ≤90% S_p,O₂ and ≥3 desaturation event clusters	HPO	Categorical	167	Chi-squared test	<0.001
Index of desaturation events to ≤90% S_p,O₂ >0.6	HPO	Categorical	167	Chi-squared test	0.023
Index of desaturation events of ≥4% S_p,O₂ >3.9 and index of desaturation event clusters >0.4	HPO	Categorical	167	Chi-squared test	0.018

SDB-Q: sleep-disordered breathing questionnaire; HPO(-Q): home pulse oximetry (questionnaire); S_p,O₂: arterial haemoglobin oxygen saturation by pulse oximetry.