TABLE 2.

Description of the respiratory polygraphy parameters by tertiles of the components derived from the PCA in the ISAACC cohort.

	Component 1			Component 2
	1st tertile	2nd tertile	3rd tertile	p for trend	1st tertile	2nd tertile	3rd tertile	p for trend
	(N = 239)	(N = 238)	(N = 246)		(N = 239)	(N = 238)	(N = 246)
RP parameters
AHI, events per h	6 [8.6]	18 [18]	35.2 [31.5]	<0.001	5.3[11.7]	15.8 [17.2]	32.8 [26.3]	<0.001
ODI > 4%, per h	4.2 [5.9]	15.1 [13.8]	32.9 [30.9]	<0.001	4 [11.6]	13 [16.7]	27.6 [25.4]	<0.001
Mean SaO2,%	94.3 [1.9]	93.2 [1.7]	91.8 [2.9]	<0.001	92.2 [3.7]	93 [2]	94 [2]	<0.001
Minimum SaO2,%	89 [4]	86 [4]	80 [8.8]	<0.001	85 [8]	86 [6]	85.5 [6]	0.312
Average duration of events, sec	19 [7]	20 [6]	20 [7.8]	<0.001	17 [6]	20 [6]	22 [8]	<0.001
Time with SaO2 < 90%,%	0 [0.3]	0.8 [2.2]	13 [29.3]	<0.001	3.1[33.4]	0.8 [5.1]	0.9 [3.8]	<0.001

Data are presented as the median [IQR (interquartile range)]. PCA, principal component analysis; RP, respiratory polygraphy; AHI, apnea-hypopnea index; ODI, oxygen desaturation index; and SaO₂, oxygen saturation. The p value for trend was calculated using Spearman’s rank correlation coefficient. Significant p values (p < 0.05) are presented in bold.