Fibromyalgia and severity measures according to WS pain and criteria categories. Values are mean (SD) unless otherwise specified.
| Variables | WPI 3–6 and SSS ≥ 9 | WPI ≥ 7 and SSS ≥ 5 | All | WS Pain | Not WS Pain |
|---|---|---|---|---|---|
| Subjects in category, n | 343 | 4668 | 5011 | 4700 | 311 |
| WPI | 4.6 (1.1) | 12.9 (4.3) | 12.3 (4.7) | 12.8 (4.5) | 6.0 (2.3) |
| SSS | 9.7 (0.8) | 7.7 (2.0) | 7.8 (2.0) | 7.8 (2.0) | 8.5 (1.9) |
| PSD | 14.3 (1.4) | 20.6 (5.2) | 20.2 (5.3) | 20.5 (5.2) | 14.5 (2.1) |
| Age, yrs | 52.3 (12.6) | 56.0 (13.0) | 55.8 (13.0) | 55.9 (13.1) | 53.4 (12.6) |
| Male, % | 7.3 | 10.6* | 10.4 | 10.5 | 8.7* |
| College graduate, % | 33.8 | 30.6* | 30.8 | 30.6 | 35* |
| HAQ, 0–3 | 1.2 (0.6) | 1.5 (0.6) | 1.5 (0.6) | 1.5 (0.6) | 1.2 (0.6) |
| Pain, 0–10 | 5.7 (2.5) | 6.4 (2.2) | 6.3(2.2) | 6.4 (2.2) | 5.5 (2.6) |
| Global severity, 0–10 | 5.6 (2.2) | 5.9 (2.1) | 5.9 (2.1) | 5.9 (2.1) | 5.3 (2.2) |
| PCS, SF-36 | 32.7 (8.3) | 28.9 (7.8) | 29.1 (7.9) | 28.9 (7.7) | 32.5 (8.9) |
| MCS, SF-36 | 34.6 (10.6) | 39.5 (11.5) | 39.1 (5.0) | 39.3 (11.5) | 37.5 (11.2) |
| PHQ-15 | 13.5 (3.1) | 13.5 (4.7)* | 13.5 (4.6) | 13.5 (4.6) | 12.4 (3.8)* |
| PHQ-4 score | 5.1 (3.6) | 4.3 (3.5)* | 4.4 (3.5) | 4.4 (3.6) | 4.9 (3.5)* |
↵The low WPI and high WPI groups (columns 2 and 3) are significantly different from each other at p < 0.5, except where flagged with asterisks (*). WS Pain and Not WS Pain groups (columns 5 and 6) are significantly different from each other at p < 0.5, except where flagged with asterisks (*). WS pain: widespread pain; WPI: Widespread Pain Index; SSS: Symptom Severity Scale; PSD: Polysymptomatic Distress Scale; HAQ: Health Assessment Questionnaire; PCS: physical component summary; SF-36: Medical Outcomes Study Short Form-36; MCS: mental component summary; PHQ-15: Patient Health Questionnaire 15; PHQ-4: Patient Health Questionnaire 4.