Table 4.

Mediators of painACTION.com intervention effects on outcome PGIC over time (excluding baseline) ^£

	Full mediation model (condition, mediator, time and interaction effects) †								Intervention over time model (condition, time and interaction effects; without the mediator) ‡
	Mediating (indirect) effects over time				Intervention (direct) effects over time with mediator in the model				Intervention (total) effects over time without mediator in the model
Putative Mediator	β coefficient	p value	F-test	p value	β coefficient	p value	F-test	p value	β coefficient	p value	F-test	p value
DASS
Depression			1.62	0.1974			2.73	0.0654			4.39	0.0125
Post	reference				reference				reference
3-month	0.0025	0.5728			−0.0438	0.6011			−0.0306	0.7178
6-month	0.0088	0.0770			0.1584	0.0912			0.2202	0.0203
Anxiety ¥			4.23	0.0147			3.73	0.0241			4.39	0.0125
Post	reference				reference				reference
3-month	0.0138	0.0144			−0.0419	0.6155			−0.0306	0.7178
6-month	0.0154	0.0117			0.1927	0.0391			0.2202	0.0203
Stress			2.99	0.0508			3.04	0.0482			4.39	0.0125
Post	reference				reference				reference
3-month	0.0008	0.8643			−0.0447	0.5962			−0.0306	0.7178
6-month	0.0117	0.0287			0.1682	0.0737			0.2202	0.0203
CPCI
Coping			0.36	0.6983			4.46	0.0118			4.39	0.0125
Post	reference				reference				reference
3-month	−0.0185	0.4039			−0.0416	0.6262			−0.0306	0.7178
6-month	−0.0133	0.5841			0.2156	0.0239			0.2202	0.0203
Relaxation			0.18	0.8385			4.17	0.0156			4.39	0.0125
Post	reference				reference				reference
3-month	−0.0062	0.7917			−0.0491	0.5654			−0.0306	0.7178
6-month	−0.0151	0.5543			0.2024	0.0337			0.2202	0.0203
Social			0.60	0.5484			4.62	0.0100			4.39	0.0125
Post	reference				reference				reference
3-month	0.0068	0.7577			−0.0315	0.7119			−0.0306	0.7178
6-month	0.0258	0.2895			0.2263	0.0174			0.2202	0.0203

PGIC = Patient Global Impression of Change; CPCI = Chronic Pain Coping Inventory; DASS = Depression Anxiety Stress Scale.

^£Baseline data excluded from analysis as PGIC was not measured.

^†Full mediation model includes the condition, mediator, time, condition*time and mediator*time as the independent variables.

^‡Reduced model includes only the condition over time effects i.e., condition, time and condition*time as the independent variables.

To infer mediation, the following type III tests of effects (F-test) must be statistically significant: (1) Intervention (total) effect over time on outcome PGIC; (2) Intervention effect over time on mediator (not shown in table); (3) Mediating (indirect) effect over time on outcome PGIC in the mediation model.

^¥Anxiety did NOT mediate the intervention effects on PGIC as the second criteria was not met.