Table III.
Unadjusted Results of Multilevel Growth Modeling Predicting the Primary and Process Outcomes From Time Since Randomization and Group Assignment
| Time effect |
Group × time effect |
|||||||
|---|---|---|---|---|---|---|---|---|
| b ± SE | β | t | ES (95% CI) | b ± SE | β | t | ES (95% CI) | |
| Primary outcomes | ||||||||
| Pain intensity NRS | −.04 ± .01 | −.08 | −3.47* | −.19/−.24 | −.01 ± .02 | −.02 | −.67 | −.09/−.01 |
| Pain interference NRS | −.04 ± .01 | −.09 | −3.99* | −.21/−.25 | −.00 ± .02 | −.01 | −.19 | −.09/−.02 |
| PedsQL rheumatology | .37 ± .05 | .13 | 7.27* | .21/.41 | .06 ± .10 | .01 | .55 | −.16/.24 |
| Process variables | ||||||||
| CASE self-efficacy | .03 ± .01 | .17 | 7.67* | .38/.40 | −.01 ± .01 | −.01 | −.44 | −.15/−.12 |
| PCQ approach coping | .00 ± .01 | .00 | .05 | .14/.16 | .01 ± .01 | .01 | .69 | .14/.16 |
| PCQ emotion-focused avoidance coping | −.01 ± .01 | −.04 | −1.60 | −.15/−.17 | .01 ± .01 | .02 | .94 | .15/.17 |
| PROMIS anxiety | −.18 ± .04 | −.07 | −3.95* | −.12/−.29 | −.13 ± .09 | −.03 | −1.43 | −.33/.03 |
| PROMIS depression | −.12 ± .05 | −.05 | −2.56* | −.05/−.23 | −.02 ± .09 | −.01 | −.24 | −.20/.16 |
| MEPS disease knowledge | .12 ± .01 | .25 | 11.43* | .60/.66 | −.01 ± .02 | −.01 | −.45 | −.09/−.01 |
Notes. *p < .05. The b-coefficient for the time effect indicates the estimated average monthly raw unit change in the given outcome variable since before starting group procedures (baseline); a significant time effect indicates that on average (across all participants) there was a significant increase or decrease in the outcome variable over months since starting group procedures. The b-coefficient for the group × time effect indicates the extent to which being in the treatment condition, relative to the control condition, increased or decreased the average monthly raw unit change on the given variable. The β-values for the time effect and group × time effect are interpreted similarly as the b-coefficients but in SD units instead of raw units. ESs are shown as the lower and upper values corresponding to the 95% CIl for the ES estimate. CI = confidence interval; ES = effect size; NRS = Numeric Rating Scale; CASE = Children’s Arthritis Self-Efficacy Scale; HRQOL = health-related quality of life; MEPS = Medical Issues, Exercise, Pain and Social Support Questionnaire; NRS = Numeric Rating Scale; PCQ = Pain Coping Questionnaire; PedsQL = Pediatric Quality of Life; PROMIS = Patient-Reported Outcomes Measurement Information System.