Table 3.
Results of the ANCOVAs and Cohen’s d for the primary and secondary outcome measures (ITT sample) at post-treatment and 6 months follow-up
| Outcome | T2† between-groups effect | T3† between-groups effect | ||
| Cohen’s d (95% CI) | ANCOVA‡ F(1,114) | Cohen’s d (95% CI) | ANCOVA‡ F(1,114) | |
| Primary outcome | ||||
| PSS-14 (0–56) | 0.74 (0.30 to 1.19) | 12.70*** | 0.59 (0.14 to 1.04) | 2.17** |
| Mental health | ||||
| SMBQ (1–7) | 0.95 (0.53 to 1.37) | 23.71*** | 0.39 (0.21 to 0.99) | 1.44 |
| Physical fatigue | 0.59 (0.17 to 1.01) | 8.36** | 0.30 (0.14 to 0.75) | 2.47 |
| Cognitive weariness | 0.57 (0.15 to 0.99) | 7.04** | 0.50 (0.05 to 0.94) | 4.71* |
| Tension | 0.36 (0.05 to 0.78) | 5.02* | 0.31 (0.13 to 0.76) | 3.88 |
| Listlessness | 0.33 (0.08 to 0.74) | 2.96 | 0.08 (0.36 to 0.52) | 0.98 |
| MADRS-S (0–54) | 0.86 (0.25 to 1.46) | 9.70* | 0.29 (0.16 to 0.74) | 1.74 |
| ISI (0–28) | 0.34 (0.07 to 0.76) | 4.85* | 0.39 (0.01 to 0.78) | 6.17* |
| Work related | ||||
| WEMS (32–192)§ | 0.59 (1.01 to 0.17) | 11.37*** | 0.11 (0.56 to 0.34) | 0.31 |
| Supportive work conditions (1–6)§ | 0.30 (0.72 to 0.13) | 4.45* | 0.05 (0.44 to 0.53) | 0.04 |
| Internal work experience (1–6)§ | 0.36 (0.78 to 0.07) | 5.77* | 0.04 (0.52 to 0.44) | 0.15 |
| Autonomy (1–6)§ | 0.12 (0.31 to 0.54) | 0.23 | 0.10 (0.38 to 0.58) | 0.60 |
| Time experience (1–6)§ | 0.16 (0.58 to 0.27) | 0.86 | 0.00 (0.48 to 0.48) | 2.58 |
| Management (1–6)§ | 0.40 (0.83 to 0.02) | 10.51** | 0.05 (0.54 to 0.43) | 0.66 |
| Process of change (1–6)§ | 0.46 (0.89 to 0.03) | 9.54** | 0.12 (0.60 to 0.36) | 0.30 |
| Absenteeism (TiC-P)¶ | 0.62 (0.45 to 1.70) | 1.59 | 0.37 (1.70 to 0.96) | 0.37 |
| Presenteeism (TiC-P)¶ | 0.29 (0.83 to 0.24) | 1.21 | 0.28 (0.91 to 0.36) | 0.78 |
| AUDIT (0–40) | – | – | – | – |
Significance levels used: *p<0.05, **p<0.01; ***p<0.001.
†Missing data imputed by multiple imputation.
‡Controlling for pretreatment scores (T1).
§Higher scores indicate better outcomes.
¶In relation to the previous month.
ANCOVA, analysis of covariance; PSS-14, Perceived Stress Scale; SMBQ, Shirom-Melamed Burnout Questionnaire; MADRS-S, Montgomery Åsberg Depression Rating Scale-self-assessment; ISI, Insomnia Severity Index; ITT, intention to treat; WEMS, Work Experience Measurement Scale; AUDIT, Alcohol Use Disorders Identification Test; TiC-P, Trimbos and Institute of Medical Technology Assessment Cost Questionnaire for Psychiatry.