Baseline demographic and clinical characteristics of the study population*
| Characteristic | Placebo (n=188) | SXB4.5g (n=195) | SXB6g (n=190) | Total (N=573) |
|---|---|---|---|---|
| Age, years | 46.8 (9.7) | 46.6 (10.8) | 46.4 (11.6) | 46.6 (10.7) |
| Female, n (%) | 168 (89.4) | 175 (89.7) | 170 (89.5) | 513 (89.5) |
| Race, n (%) | ||||
| White | 173 (92.0) | 182 (93.3) | 169 (88.9) | 524 (91.4) |
| Black | 10 (5.3) | 11 (5.6) | 18 (9.5) | 39 (6.8) |
| Other | 5 (2.7) | 2 (1.0) | 3 (1.6) | 10 (1.7) |
| Body mass index, kg/m2 | 27.4 (4.7) | 27.4 (4.3) | 28.0 (4.8) | 27.6 (4.6) |
| Time since first fibromyalgia symptoms, years, mean (SD) | 9.3 (7.9) | 9.9 (8.8) | 9.9 (9.5) | 9.7 (8.8) |
| Time since first fibromyalgia diagnosis, years, mean (SD) | 5.1 (6.3) | 5.1 (5.5) | 4.4 (5.0) | 4.9 (5.6) |
| Previous pharmacological treatment for fibromyalgia, n (%) | 182 (96.8) | 185 (94.9) | 182 (95.8) | 549 (95.8) |
| Previous non-pharmacological treatment for fibromyalgia, n (%) | 132 (70.2) | 128 (65.6) | 138 (72.6) | 398 (69.5) |
| Baseline scores | ||||
| Pain VAS (scale 0–100) | 72.6 (12.9) | 70.5 (13.0) | 72.2 (14.0) | 71.8 (13.3) |
| Fatigue VAS (scale 0–100) | 73.5 (15.0) | 71.1 (15.4) | 71.5 (17.2) | 72.0 (15.9) |
| TPC (scale 0–18), median (range)† | 18.0 (8, 18) | 18.0 (11, 18) | 18.0 (12, 18) | 18.0 (8, 18) |
| TPI (scale 0–72) | 39.5 (12.2) | 37.9 (11.7) | 38.2 (11.4) | 38.6 (11.7) |
| MTPS (scale 0–180) | 111.3 (33.3) | 112.3 (32.4) | 109.2 (30.9) | 111.0 (32.2) |
| FIQ total score (scale 0–100) | 63.7 (14.1) | 62.3 (15.2) | 62.1 (15.1) | 62.7 (14.8) |
| SF-36 PCS (scale 0–100) | 29.1 (7.9) | 29.6 (8.7) | 30.8 (7.5) | 29.8 (8.1) |
| EQ-5D overall health state | 46.6 (22.95) | 48.8 (22.25) | 47.4 (24.00) | 47.6 (23.06) |
| JSS total score (scale 0–20), median (range)† | 16.0 (3, 20) | 16.0 (0, 20) | 16.0 (2, 20) | 16.0 (0, 20) |
| FOSQ (scale 5–20) | 13.4 (3.8) | 13.4 (3.8) | 13.7 (3.8) | 13.5 (3.8) |
| CGIS (scale 1–7) | 4.3 (1.1) | 4.5 (1.0) | 4.4 (1.0) | 4.4 (1.0) |
↵* Except when indicated otherwise, values are mean (±SD).
↵† Median values are presented due to skewed distribution of data.
CGIS, clinical global impression of severity; EQ-5D, EuroQol-5 dimensions self-report questionnaire; FIQ, fibromyalgia impact questionnaire; FOSQ, functional outcomes of sleep questionnaire; JSS, Jenkins sleep scale; MTPS, manual tender point survey; PCS, physical component summary; SD, standard deviation; SF-36, Medical Outcomes Study 36-item short-form health survey; SXB4.5g, sodium oxybate 4.5 g/night; SXB6g, sodium oxybate 6 g/night; TPC, tender-point count; TPI, tender-point index; VAS, visual analogue scale.