Table IV.

Results of Multilevel Growth Modeling Evaluating Predictors of Change in the Primary Outcome Variables of Pain and HRQOL

Predictors	Outcomes
	Pain intensity			Pain interference			HRQOL
	b ± SE	β	t	b ± SE	β	t	b ± SE	β	t
CASE self-efficacy	−3.11 ± .82	−.08	−3.80*	−3.26 ± .71	−.10	−4.61*	16.26 ± 3.70	.10	4.40*
PCQ approach coping	1.04 ± .56	.04	1.83	.57 ± .45	.03	1.25	−1.48 ± 2.36	.00	.53
PCQ emotion-focused avoidance coping	1.10 ± .33	.06	3.33*	1.00 ± .29	.06	3.42*	−9.12 ± 2.15	−.08	−4.23*
PROMIS anxiety scale	1.46 ± .42	.09	3.47*	1.46 ± .47	.10	3.10*	−16.42 ± 2.94	−.13	−5.57*
PROMIS depression scale	.67 ± .38	.08	1.76	.91 ± .33	.10	2.69*	−9.52 ± 1.90	−.10	−4.88*
MEPS disease knowledge	.46 ± .24	.03	1.94	.24 ± .21	.02	1.14	3.44 ± 1.30	.04	2.65*

Notes. * p < .05. Positive b-values indicate the amount of increase expected in the given outcome variable for each raw unit increase (since preintervention) in the given predictor variable; positive β-values indicate the same but in SD units rather than raw units. Negative b-values indicate the expected amount of reduction in the given outcome variable for each raw unit increase (since preintervention) in the given predictor variable; negative β-values indicate the same but in standard deviation units rather than raw units. Pain intensity and pain interference were measured on numeric rating scales with a potential range from 0 to 10, with higher scores indicating greater pain intensity and pain interference. HRQOL (average item score from PedsQL Rheumatology Module) was measured on a scale ranging from 0 to 100, with higher scores indicating better HRQOL. CASE = Children’s Arthritis Self-Efficacy Scale; HRQOL = health-related quality of life; MEPS = Medical Issues, Exercise, Pain and Social Support Questionnaire; PCQ = Pain Coping Questionnaire; PROMIS = Patient-Reported Outcomes Measurement Information System.