Table 2.
Parameter estimates (95% confidence intervals) from multivariate linear mixed models with the following explanatory variables (one model per dependent variable) (i.e. average differences in outcome variables of knee pain and functioning between groups of categorical predictors).
| Parameter | WOMAC pain | WOMAC function | RAND-36 function | RAND-36 PCS (orthogonal) | RAND-36 MCS (orthogonal) | RAND-36 PCS (oblique) | RAND-36 MCS (oblique) |
|---|---|---|---|---|---|---|---|
| Life Satisfaction score (satisfied 4−11, n = 99 vs. dissatisfied 12−20, n = 12) | −0.65 (−9.94 to 8.64) | −2.15 (−12.32 to 8.03) | 17.47**g (6.54 to 28.40) | 2.68 (−2.03 to 7.39) | 6.24*m (1.48 to 11.00) | 4.52*q (0.25 to 8.79) | 5.74**m (1.83 to 9.65) |
| Sense of Coherence score (59−84, n = 72 vs. 37−58, (lowest tertile) n = 39) | 2.64 (−2.98 to 8.27) | 2.56 (−3.64 to 8.77) | −1.58 (−8.31 to 5.16) | −1.41 (−4.27 to 1.45) | 0.81 (−2.08 to 3.71) | −1.09 (−3.70 to 1.52) | 0.66 (−1.73 to 3.05) |
| Pain Self-Efficacy Questionnaire score (41−60, n = 73 vs. 0−40 (lowest tertile), n = 38) | 1.68 (−4.49 to 7.84) | −4.79 (−11.57 to 1.98) | 9.48*h (2.14 to 16.82) | 3.03 (−0.11 to 6.17) | 4.70**n (1.52 to 7.87) | 4.42**r (1.56 to 7.28) | 4.89***n (2.27 to 7.52) |
| Tampa Scale of Kinesiophobia score (0−36, n = 75 vs. 37−68, n = 36) | −5.04 (−11.39 to 1.31) | −7.09*d (−14.07 to −0.11) | 8.69*i (1.16 to 16.22) | 3.19 (−0.05 to 6.42) | 3.50*o (0.23 to 6.77) | 4.05**s (1.11 to 6.99) | 3.89**o (1.19 to 6.58) |
| Pain Catastrophizing Scale score (0−18, n = 72 vs. 19−50 (highest tertile), n = 39) | −7.93*a (−14.17 to −1.69) | −3.20 (−10.08 to 3.68) | −1.88 (−9.33 to 5.57) | 0.47 (−2.69 to 3.64) | −1.43 (−4.63 to 1.77) | −0.20 (−3.08 to 2.68) | −0.96 (−3.60 to 1.68) |
| Beck Depression Inventory (normal mood 0–9, n = 92 vs. mild depressive symptoms or more 10−63, n = 19) | −2.83 (−10.63 to 4.98) | −4.80 (−13.40 to 3.79) | −2.55 (−11.87 to 6.78) | 0.59 (−3.41 to 4.60) | 2.67 (−1.38 to 6.72) | 1.65 (−1.99 to 5.30) | 2.59 (−0.75 to 5.93) |
| Beck Anxiety Inventory (normal mood 0–7, n = 58 vs. mild anxiety or more 8–63, n = 53) | −7.09*b (−13.23 to −0.95) | −11.02**e (−17.79 to −4.25) | 11.82**j (4.50 to19.14) | 3.78*k (0.68 to 6.88) | 5.90***p (2.76 to 9.03) | 5.65***k (2.82 to 8.47) | 6.15***p (3.56 to 8.74) |
| Group randomization (CBT intervention n = 55 vs. control n = 56) | −2.47 (−7.83 to 2.88) | 0.34 (−5.54 to 6.23) | −0.13 (−6.49 to 6.24) | −0.28 (−3.00 to 2.45) | −1.45 (−4.20 to 1.30) | −0.78 (−3.25 to 1.70) | −1.13 (−3.40 to 1.14) |
| Time (baseline vs. follow-up average) | 19.17***c (15.42 to 22.92) | 13.96***f (10.24 to 17.68) | −1.04 (−4.27 to 2.20) | −2.18**l (−3.68 to −0.68) | 1.36 (−0.14 to 2.86) | −1.40*l (−2.67 to −0.13) | 0.30 (−0.84 to 1.43) |
WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index (visual analogue scale (VAS) mm); RAND-36: Finnish-validated SF-36-item Health Survey; PCS: physical component summary; MCS: mental component summary. *P ⩽ 0.05; **P ⩽ 0.01; ***P ⩽ 0.001.
7.93 lower pain score for those with low Pain Catastrophizing Scale scores. b7.09 lower pain score for those with a normal mood. c19.17 higher pain score at baseline. d7.09 lower functional impairment for those with low Tampa Scale of Kinesiophobia scores. e11.02 lower functional impairment for those with normal mood. f13.96 higher functional impairment at baseline. g17.47 better physical function for the satisfied. h9.48 better physical function for those with high Pain Self-Efficacy Questionnaire scores. i8.69 better physical function for those with low Tampa Scale of Kinesiophobia scores. j11.82 better physical function for those with a normal mood. k3.78/5.65 higher PCS scores (orthogonal/oblique) for those with normal mood. l2.18/1.40 lower PCS scores (orthogonal/oblique) at baseline. m6.24/5.74 higher MCS scores (orthogonal/oblique) for the satisfied. n4.70/4.89 higher MCS scores (orthogonal/oblique) for those with high Pain Self-Efficacy Questionnaire scores. o3.50/3.89 higher MCS scores (orthogonal/oblique) for those with low Tampa Scale of Kinesiophobia scores. p5.90/6.15 higher MCS scores (orthogonal/oblique) for those with a normal mood. q4.52 higher PCS scores (oblique) for the satisfied. r4.42 higher PCS scores (oblique) for those with high Pain Self-Efficacy Questionnaire scores. s4.05 higher PCS scores (oblique) for those with low Tampa Scale of Kinesiophobia scores.