Mixed-model analyses of intermediate outcomes for participants in TAU+OT (n=78) and TAU (n=39)
| Outcome variable | 6 months (T1) | 12 months (T2) | 18 months (T3) | Model | B (95% CI) | p |
|---|---|---|---|---|---|---|
| Self-efficacy | Group | 1.0 (−3.5 to 5.6)* | 0.66 | |||
| TAU+OT | 3.4 (1.1) | 3.9 (1.1) | 4.2 (1.0) | Time | 4.2 (3.3 to 5.1)* | <0.001 |
| TAU | 3.2 (1.4) | 3.8 (1.2) | 4.0 (1.7) | Group×Time | −0.2 (−2.2 to 1.8)* | 0.83 |
| Adjusted effect OT (Δ)† | +1.2 | +1.0 | +0.8 | |||
| (−3.8 to +6.2) | (−3.5 to +5.6) | (−4.2 to +5.8) | ||||
| UCL active problem solving‡ | Group | 1.2 (−0.2 to 2.6) | 0.10 | |||
| TAU+OT | 16.6 (3.8) | 17.2 (3.6) | 17.9 (3.7) | Time | 0.7 (0.3 to 1.0) | <0.001 |
| TAU | 15.4 (3.7) | 16.3 (3.9) | 16.8 (3.9) | Group×Time | −0.1 (−0.7 to 0.6) | 0.82 |
| Adjusted effect OT (Δ)† | +1.3 | +1.2 | +1.1 | |||
| (−0.3 to +2.8) | (−0.2 to +2.6) | (−0.4 to +2.6) | ||||
| UCL avoidance‡ | Group | −0.3 (−1.4 to 0.9) | 0.68 | |||
| TAU+OT | 17.2 (3.2) | 16.7 (2.9) | 16.9 (3.3) | Time | −0.3 (−0.6 to 0.0) | 0.05 |
| TAU | 18.3 (3.7) | 16.4 (3.7) | 17.1 (3.5) | Time2 | 0.7 (0.1 to 1.4) | 0.04 |
| Adjusted effect OT (Δ)† | −0.7 | −0.3 | +0.2 | Group×Time | 0.5 (−0.2 to 1.1) | 0.19 |
| (−2.1 to +0.7) | (−1.4 to +0.9) | (−1.6 to +1.2) | Group×Time2 | −0.8 (−2.0 to 0.3) | 0.16 | |
| UCL passive reaction‡ | Group | −0.6 (−2.0 to 0.9) | 0.43 | |||
| TAU+OT | 15.8 (4.4) | 13.4 (3.4) | 13.1 (3.3) | Time | −1.3 (−1.7 to −0.9) | <0.001 |
| TAU | 16.5 (4.4) | 14.6 (4.5) | 14.1 (4.4) | Time2 | 0.9 (0.3 to 1.5) | <0.001 |
| Adjusted effect OT (Δ)† | −0.4 | −0.6 | −0.7 | Group×Time | −0.2 (−0.9 to 0.6) | 0.68 |
| (−2.0 to +1.2) | (−2.0 to +0.9) | (−2.4 to +0.9) | Group×Time2 | 0.3 (−1.0 to 1.7) | 0.26 | |
Data are mean (SD), unless stated otherwise. All analyses are adjusted for covariates (propensity score) and baseline measure. TAU is the reference category for Group, Time is coded as −1(T1), 0(T2), 1(T3). Time2 is coded as 1(T1), 0(T2), 1(T3).
*Analysis is based on change scores from baseline.
†Adjusted differences between treatment groups and their 95% CIs.
‡As the baseline UCL scales reflect a variable time period (ie, the period before the start of sickness absence), we were not able to conduct analyses based on change scores from baseline (see ‘Statistical Analyses’ for further information).
OT, occupational therapy; TAU, treatment-as-usual; UCL, Utrecht Coping List.