More severe hypoxemia is associated with better subjective sleep quality in obstructive sleep apnea

BMC Pulmonary Medicine

Table 3 Multiple linear regression (stepwise with mixed entry)

Term	Coefficient	SE	Lower 95 %	Upper 95 %	p-value
Intercept	12.866	2.000	8.913	16.818	<.0001
C-age (years)	0.053	0.023	0.007	0.099	0.025*
C-total sleep time (mins)	−0.010	0.005	−0.021	0.001	0.064
PLMI (/hr)	0.618	0.385	−0.142	1.378	0.110
Tendency of depression	2.378	0.636	1.120	3.635	<.0001*
C-lowest 5 % SpO2 (%)	−0.263	0.128	−0.516	−0.009	0.042*
Median SpO2-Lowest 5% SpO2	−0.357	0.145	−0.644	−0.070	0.015*

*p < 0.05
Abbreviations: C-age centering of age (age minus the mean of age); C-total sleep time centering of total sleep time (total sleep time minus the mean of total sleep time); C-lowest 5 % SpO2 centering of the averaged value from the lowest 5 % saturation of total sleep time (lowest 5 % SpO2 minus the mean of lowest 5 % SpO2). These centering were performed since collinearity was diagnosed; PLMI periodic leg movements index; tendency of depression was defined as either CES-D ≥15 or HADS-D ≥ 8; median SpO2-lowest 5 % SpO2 difference between median to lowest 5 % of saturation of total sleep time. Median SpO2 minus Lowest 5 % SpO2 was the independent predictor for lower PSQI after adjusting other variables

ISSN: 1471-2466