Table 4.

Associations Between Biobehavioral Factors and Global Sleep Quality (N = 228)

Measure	Mixed-effects models				Fixed-effects models
	Coef.	SE	z	p	Coef.	SE	t	p
Anxiety	0.75	0.09	8.48	<0.001	0.53	0.10	5.59	<0.001
Depression	1.24	0.06	20.43	<0.001	1.06	0.07	14.60	<0.001
Well Being	−0.70	0.12	−5.76	<0.001	−0.38	0.14	−2.70	<0.01
IL-6	1.04	0.53	1.99	0.047	0.79	0.60	1.33	0.186
TNFα	−0.45	0.46	−0.99	0.324	−0.49	0.53	−0.92	0.358

Note. A subsample of n = 91 participants were included in the IL-6 and TNFα models which did not include the twelve month post-transplant time point. Separate models were run for each psychological measure or cytokine. Mixed-effects models covaried for time (treated as a factor variable); age, sex, graft type, and conditioning regimen (between-subjects covariates); and steroid use and disease status (time-varying covariates). Fixed effects models covaried for time and time-varying covariates. Psychological symptom scores were standardized before being entered in the model; therefore, coefficients represent the change in mean PSQI score for each one standard deviation increase in psychological symptoms. Cytokine concentrations were coded as elevated or normal; therefore, coefficients represent the difference in PSQI scores for elevated versus normal cytokine levels.