Table 1. Clinical and laboratory characteristics of groups.* .
| RA with FM (n = 36) | RA without FM (n = 36) | P value ¶ | |
|---|---|---|---|
| Demographic | |||
| Age (years) | 57.5 (50.0, 66.5) | 57.5 (48.3, 66.8) | 0.62 |
| White (%) | 97 | 81 | 0.07 |
| Education level ≤ 4 years (%) | 69 | 69 | 1.00 |
| Medical | |||
| Sjögren’s syndrome (%) | 17 | 8 | 0.45 |
| Fibromyalgia | |||
| FM duration (years) | 6.0 (2.0, 15.0) | - | - |
| Tender points (0–18) § | 14.0 (12.0, 16.75) | 4.0 (2.0, 6.0) | <0.001 |
| FIQ (0–100) § | 56.8 (40.5, 74.7) | - | - |
| FIQ pain (0–10) § | 6.1 (1.9, 9.5) | - | - |
| Pain medications† use (%) | 64 | 22 | <0.001 |
| Rheumatoid arthritis | |||
| RA duration (years) | 12.5 (6.0, 19.0) | 13.0 (6.0, 17.8) | 0.60 |
| Rheumatoid factor (+) (%) | 78 | 78 | 1.00 |
| Erosion on radiograph (%) | 64 | 69 | 0.73 |
| Conventional DMARD use (%) | 97 | 97 | 1.00 |
| Biologic DMARD use (%) | 19 | 17 | 0.82 |
| NSAID use (%) | 9 | 22 | 0.13 |
| Prednisone dose (mg/day) | 1.5 (0.0, 10.0) | 2.5 (0.0, 10.0) | 0.61 |
| HAQ (0–3) § | 1.6 (0.9, 2.1) | 0.9 (0.4, 1.3) | <0.01 |
| DAS28 (0–9.4) § | 5.2 (4.3, 6.3) | 4.0 (3.3, 4.6) | <0.001 |
| SDAI (0–86) § | 31.1 (18.0, 40.3) | 13.1 (9.0, 22.4) | <0.001 |
| CDAI (0–76) § | 30.4 (18.0, 39.7) | 13.1 (8.0, 22.1) | <0.001 |
| Tender joints count (0–28) § | 14.0 (7.0, 22.8) | 2.5 (1.0, 6.0) | <0.001 |
| Swollen joints count (0–28) § | 5.0 (1.3, 8.0) | 3.0 (2.0, 6.0) | 0.25 |
| Patient visual analog scale (0–100) § | 59.5 (39.5, 76.8) | 38.0 (17.3, 59.3) | <0.01 |
| Erythrocyte sedimentation rate (mm/h) | 12.5 (7.0, 31.0) | 19.5 (9.0, 32.8) | 0.16 |
| C-reactive protein (mg/l) | 10.1 (0.0, 13.6) | 5.1 (4.0, 11.0) | 0.14 |
| GS-US7 | 10.0 (7.0, 11.0) | 9.0 (7.0, 11.0) | 0.37 |
| PD-US7 | 3.0 (1.0, 5.8) | 4.0 (2.0, 5.0) | 0.87 |
| Synovial hypertrophy on US (%) | 100 | 100 | 1.00 |
| Synovial effusion on US (%) | 33 | 44 | 0.34 |
RA: rheumatoid arthritis; FM: fibromyalgia; FIQ: fibromyalgia impact questionnaire; FIQ pain: “How much pain did you experience in the last seven days?”; RA: rheumatoid arthritis; DMARD: disease-modifying antirheumatic drugs; NSAID: non-steroidal anti-inflammatory drugs; mg: milligrams; HAQ: health assessment questionnaire; DAS28: disease activity score of 28 joints with 4 variables (tender joints count, swollen joint count, patient visual analog scale, erythrocyte sedimentation rate); SDAI: simplified disease activity index with 5 variables(tender joints count, swollen joint count, patient visual analog scale, physician visual analog scale, C-reactive protein); CDAI: clinical disease activity index with 4 variables (tender joints count, swollen joint count, patient visual analog scale, physician visual analog scale); GS-US7: gray-scale 7-joint ultrasound score; PD-US7: power Doppler 7-joint ultrasound score; US: ultrasound.
*Values are median (25th, 75th percentiles) or percentage
¶Two-tailed Wilcoxon’s or McNemar’s tests; P<0.05
§Score (range)
†Pain medications: tricyclic antidepressants, selective serotonin reuptake inhibitors, cyclobenzaprine, duloxetine, pregabalin or tramadol