Table 3.
Difference in difference analysis of the clinical outcomes.
| Response variable | Placebo group | Treated group | DD: Treated - Placebo | ||||||
|---|---|---|---|---|---|---|---|---|---|
|
|
|
|
|||||||
| T0 | W8 | W8 - T0* | T0 | W8 | W8 - T0* | mean | SE | P-value | |
| WPI | 15.27 | 13.36 | −1.91 (4.55) | 16.60 | 3.70 | −12.90 (5.32) | −10.99 | 2.15 | < 0.01 |
| SS score | 8.09 | 6.09 | −2.00 (2.32) | 8.40 | 4.30 | −4.10 (2.85) | −2.10 | 1.13 | 0.0392 |
| VAS pain | 56.82 | 40.00 | −16.82 (23.69) | 75.00 | 27.00 | −48.00 (30.75) | −31.18 | 11.91 | 0.0085 |
| FIQ | 54.88 | 42.20 | −12.67 (19.06) | 53.74 | 31.96 | −21.78 (19.29) | −9.11 | 8.38 | 0.1452 |
| SF-36 | 47.39 | 61.49 | 14.10 (13.64) | 44.07 | 66.39 | 22.32 (16.85) | 8.22 | 6.66 | 0.1162 |
*
Mean difference; SD of the difference in brackets.
WPI: widespread pain index; SS score: symptom severity scale; VAS: visual analog scale; FIQ: fibromyalgia impact questionnaire; SF-36: short form 36 health survey questionnaire.