Table 2.

Logistic regression models predicting study outcomes on sleepiness, near-crashes, fatigue-related work errors, stress and burnout

Dependent variable	Model χ2 (7df), sig value	Variance explained*	Significant predictors†	OR (95% CI)
ESS score >10	49.953, p<0.001	0.019–0.026	Medication with sleepiness as a side effect	1.58 (1.19 to 2.10)
			Night-shift work	1.48 (1.22 to 1.80)
			Wake-promoting meds × night-shift work	2.56 (1.19 to 5.54)
Near-crash	73.987, p<0.001	0.026–0.038	Sleep-promoting medication	1.61 (1.21 to 2.13)
			Medication with sleepiness as a side effect	1.38 (1.04 to 1.82)
			Night-shift work	1.48 (1.20 to 1.81)
Fatigue-related errors	197.398, p<0.001	0.065–0.091	Wake-promoting medication	1.68 (1.01 to 2.79)
			Sleep-promoting medication	1.75 (1.32 to 2.30)
			Medication with sleepiness as a side effect	1.57 (1.19 to 2.07)
			Night-shift work	2.40 (1.97 to 2.92)
Stress‡	58.297, p<0.001	0.025–0.034	Wake-promoting medication	1.74 (1.06 to 2.89)
			Sleep-promoting medication	1.41 (1.10 to 1.82)
			Medication with sleepiness as a side effect	1.39 (1.08 to 1.78)
			Age	0.985(0.976 to 0.994)
Burnout§	106.26, p<0.001	0.043–0.058	Sleep promoting medication	1.83 (1.40 to 2.38)
			Medication with sleepiness as a side effect	1.82 (1.40 to 2.37)
			Age	0.989 (0.98 to 0.99)
			Gender	0.78 (0.64 to 0.96)

*Estimates here represent Cox & Snell R-Square and Nagelkerke R-square values.

†Predictors and levels entered into the model: wake medications: used in the past month versus not used, sleep medications: used in the past month versus not used, medication with sleepiness as a side effect: used in the past month versus not used, night-shifts: worked versus not. Only variables significantly contributing to the model are included in the table. Model controlled for age and gender.

‡Scores of 5–7 on a seven-point Likert-type scale.

§Created using Maslach’s burnout scale (emotional subscale) – scores of 18+ used to reflect moderate-high burnout.

ESS, Epworth Sleepiness Scale.