TABLE 2

False positive and false negative rates of arterial oxygen saturation (S_aO₂) at the threshold of ≤88% to identify severe hypoxaemia in COPD

Severe hypoxaemia defined as	S_aO₂≤88% false positive rate		S_aO₂≤88% false negative rate
Severe hypoxaemia defined as	COPD (Cohort 1+2)	Validation (Cohort 3)	COPD (Cohort 1+2)	Validation (Cohort 3)
NOTT criteria [1] %	1.7^#		39.6^#
P_aO₂ ≤55 mmHg %	4.7^¶	3.3⁺	21.9^¶	15.7⁺
P_aO₂ <60 mmHg %	0.5^¶	0⁺	45.4^¶	40.3⁺

NOTT: Nocturnal Oxygen Therapy Trial; P_aO₂: arterial oxygen tension. ^#: details are provided in supplementary Table 3S. ^¶: details are provided in supplementary Table 4S. ⁺: details are provided in supplementary Table 5S.