Comparison of unblinded and blinded patients at 1 year
| Variable | Unblinded | Blinded | Unadjusted P |
|---|---|---|---|
| Mean Roland score | 4.9 (SD = 5.3) | 4.2 (SD = 5.3) | .386 |
| Mean VPAS for average pain | 2.9 (SD = 2.4) | 2.8 (SD = 2.8) | .407 |
| Mean VPAS for worst pain | 4.5 (SD = 3.1) | 3.9 (SD = 3.3) | .221 |
| Mean no. of sick days | 0.27 (SD = 0.85) | 0.34 (SD = 3.3) | .493 |
| Mean self-efficacy pain | 72.0 (SD = 23.6) | 73.9 (SD = 21.8) | .749 |
| Mean self-efficacy other | 75.7 (SD = 21.6) | 76.9 (SD = 9.9) | .810 |
| Mean FAQ physical activity | 13.3 (SD = 7.0) | 13.9 (SD = 6.5) | .589 |
| Mean FAQ work | 11.2 (SD = 10.5) | 11.7 (SD = 9.9) | .770 |
| Mean SF-36: PF | 75.0 (SD = 25.4) | 75.7 (SD = 24.2) | .903 |
| Mean SF-36: RP | 72.5 (SD = 38.3) | 73.5 (SD = 40.8) | .607 |
| Mean SF-36: BP | 64.1 (SD = 26.5) | 64.7 (SD = 26.8) | .888 |
| Mean SF-36: GH | 70.2 (SD = 24.7) | 75.2 (SD = 18.2) | .461 |
| Mean SF-36: VT | 58.9 (SD = 22.1) | 62.4 (SD = 21.7) | .362 |
| Mean SF-36: SF | 85.9 (SD = 24.9) | 86.7 (SD = 22.8) | .980 |
| Mean SF-36: RE | 83.1 (SD = 33.1) | 87.4 (SD = 28.0) | .665 |
| Mean SF-36: MH | 74.3 (SD = 20.2) | 81.0 (SD = 16.7) | .032* |
Note:—SD indicates standard deviation; VPAS, visual pain analog scale; FAQ, fear avoidance questionnaire; SF, short form; PF, physical functioning; RP, role-physical; BP, bodily pain; GH, general health; VT, vitality; SF, social functioning; RE, role-emotional; MH, mental health.
* The P value for mental health, after adjusting for the multiple comparisons, was >.05, not statistically significant.