TABLE 3.

Tests of Mediation for Daytime Symptoms between Sleep Disturbance and Functional Performance using Bootstrapping Methods

		DV: Physical functiona		DV: 6MWT
IV: Sleep disturbance	M: Daytime symptom	DE 95% CI	IE 95% CI	DE 95% CI	IE 95%CI
Insomnia severity	Fatigueb	−.08 [−.20, .04]	−.11** [−.18, −.06]	−.02 [−.16, .12]	−.05 [−.10, .003]
	Daytime sleepinessc	−.15** [−.27, −.04]	−.02 [−.05, .001]	−.04 [−.05, .87]	−.004 [−.03, .02]
	Depressive symptomsd	−.11 [−.24, .02]	−.06** [−.12, −.01]	−.01 [−.16, .13]	−.03 [−.09, .04]
Sleep quality	Fatigueb	−.15** [−.28, −.01]	−.13** [−.20, −.06]	−.15 [−.31, .02]	−.04 [−.12, .02]
	Daytime sleepinessc	−.19** [−.32, −.06]	−.03** [−.07, −.001]	−.13 [−.27, .01]	−.002 [−.04, .03]
Respiratory disturbancee	Depressive symptomsd	−.17** [−.30, .03]	−.06 [−.12, .001]	−.12 [−.29, .05]	−.01 [−.09, .05]
	Fatigueb	−.11 [−.23, .07]	−.01 [−.07, .04]	.05 [−.09, .20]	−.01 [−.04, .02]
	Daytime sleepinessc	−.09 [−.21, .04]	−.03** [−.06, −.003]	.04 [−.10, .18]	−.01 [−.03, .02]
	Depressive symptomsd	−.13** [−.24, −.01]	.03 [−.02, .05]	.03 [−.11, .17]	.01 [−.01, .03]

Note. N = 173. The direct effects (effect of sleep disturbance on functional performance after controlling for daytime symptoms) and indirect effects (mediation effect through daytime symptoms) were estimated from 2000 bootstrap samples with replacement. The effects were adjusted for age, gender, New York Heart Association Functional Classification, and comorbidity. 6MWT = Six-Minute Walk Test; CESD = ; CI = confidence interval; DE = direct effect; DV = dependent variable; ESS = ; GFI = ; IE = indirect effect; IV = independent variable; M = mediator; RDI = Respiratory Disturbance Index.

^aPhysical Function—Medical Outcomes SF-36 score.

^bGFI score.

^cESS score.

^dCESD score.

^eRDI score.

^**p < .05.