Table 2.

Pain Change as a Predictor of Depression and Depression Change as a Predictor of Pain over 12 Months^*

Sample	Predictor (Independent) Variable
	Model A Pain (GCPS Severity) Change [predicting depression]			Model B Depression (HSCL-20) Change [predicting pain]
	Beta	T	P	Beta	T	P
Primary analysis
Full sample (n = 500)
Unadjusted	.0030	4.31	< .0001	5.15	4.38	< .0001
Adjusted for covariates	.0030	4.40	< .0001	5.33	4.54	< .0001
Fully adjusted for covariates + baseline value of outcome variable	.0043	6.62	< .0001	7.23	6.46	< .0001
Secondary analyses
Clinical trial group (n = 250)
Unadjusted	.0045	5.49	< .0001	5.33	4.89	< .0001
Adjusted for covariates	.0045	5.45	< .0001	5.32	4.88	< .0001
Fully adjusted for covariates + baseline value of outcome variable	.0047	5.81	< .0001	5.52	5.15	< .0001
Intervention arm in clinical trial (n = 123)
Fully adjusted for covariates + baseline value of outcome variable	.0035	3.36	.0009	4.57	2.90	.004
Control arm in clinical trial (n = 127)
Fully adjusted for covariates + baseline value of outcome variable	.0063	4.87	< .0001	6.84	4.74	< .0001
Nondepressed cohort group (n = 250)
Fully adjusted for covariates + baseline value of outcome variable	.0026	3.59	.0004	9.50	4.42	< .0001

^*Mixed effects repeated measures multivariable models examining preceding pain change as a predictor of subsequent depression (Model A), and preceding depression change as a predictor of subsequent pain (Model B). A positive coefficient means that improvement in the predictor variable is associated with reduction in the severity of the outcome variable, while worsening in the predictor variable is associated with an increase in severity of the outcome variable.

Covariates controlled for in models were age, sex, race, pain location, study site, and time in months since baseline.