. 2013 Sep 30;9:1483–1494. doi: 10.2147/NDT.S50763

Table 4.

Univariate and multiple logistic regressions

	Univariate logistic regressions			Multiple logistic regressions
	OR	95% CI	P-value	OR	95% CI	P-value
FSS⁴
AHI/hour	*1.011*	*1.001–1.020*	*0.033*	1.005	0.992–1.017	0.484
SpO2% min	0.978	0.957–1.000	0.051
Sleep efficacy (% TST/TiB)	0.994	0.977–1.011	0.459
NREM-3/4 (% of TiB)	1.007	0.988–1.025	0.479
Number of awakenings	*1.024*	*1.000–1.049*	*0.047*	1.018	0.993–1.043	0.155
Arousal index/hour	*1.020*	*1.004–1.036*	*0.017*	*1.022*	*1.001–1.044*	*0.043*
Sleep latency (minutes)	1.003	0.995–1.012	0.416
Age (years)	*0.977*	*0.960–0.995*	*0.010*	*0.974*	*0.956–0.992*	*0.006*
Sex (F/M)	*2.047*	*1.259–3.327*	*0.004*	*2.387*	*1.418–4.020*	*0.001*
MFIS²
AHI/hour	1.008	0.998–1.017	0.106
SpO2% min	1.002	0.982–1.023	0.817
Sleep efficacy (% TST/TiB)	1.004	0 .989–1.020	0.598
NREM-3/4 (% of TiB)	1.006	0.988–1.023	0.517
Number of awakenings	1.052	*1.023–1.081*	*<0.0001*	*1.043*	*1.015–1.073*	*0.002*
Arousal index/hour	1.009	0.994–1.024	0.255
Sleep latency (minutes)	0.998	0.991–1.005	0.606
Age (years)	0.981	*0.964–0.964*	*0.026*	*0.981*	*0.964–0.999*	*0.042*
Sex (F/M)	2.377	*1.483–3.811*	*<0.0001*	*2.108*	*1.292–3.441*	*0.003*

Notes: The independent variables in the first regression include all polysomnographic parameters and age and sex. All variables that were significant in the first univariate analysis (age, sex, the number of awakenings, and for FSS values, additionally, arousal index and AHI) remained in the final model of multiple logistic regressions. The independent variables age and sex predict high FSS and MFIS values after multiple logistic regressions. In addition, a high number of awakenings predict high MFIS values, and a high arousal index predicts high FSS values. ORs were calculated, which reflect the probability to develop fatigue measured with MFIS and FSS. Bold italic font indicates significant odds ratios.

Abbreviations: AHI, apnea/hypopnea index; CI, confidence interval; FSS, Fatigue Severity Scale; MFIS, Modified Fatigue Impact Scale; NREM-3/4, non-rapid eye movement sleep stage 3/4; OR, odds ratio; SpO2% min, minimal desaturation; TiB, time in bed; TST, total sleep time; F, female; M, male.