Table 1.
Characteristics of the sample.
| Characteristic | Healthy subjects (n = 14) | Myofascial pain syndrome (n = 54) | Fibromyalgia (n = 19) | Osteoarthritis (n = 27) | P |
|---|---|---|---|---|---|
| Age (years) | 32.43 (10.81) | 46.13 (12.10) | 50.42 (8.84) | 64.42 (7.81) | 0.00 |
| Body mass index (kg/m2) | 23.12 (2.93) | 25.22 (4.37) | 31.81 (7.08) | 28.52 (5.52) | 0.00 |
| Years of education | 17.14 (2.53) | 10.16 (3.61) | 13.29 (4.04) | 10.37(5.61) | 0.00 |
| Employed (yes/no) | 14/0 | 45/9 | 16/3 | 19/8 | 0.19 |
| Smoking (yes/no) | 0/14 | 2/52 | 5/14 | 0/27 | 0.14 |
| History of psychiatric disorder (yes/no)* | NA | 19/35 | 7/12 | 5/22 | 0.24 |
| Drug active on the nervous system (yes/no)** | NA | 17/37 | 11/8 | 12/15 | 0.11 |
| Tricyclic antidepressant (yes/no) | NA | 7/47 | 7/12 | 1/26 | – |
| Selective serotonin reuptake inhibitor (yes/no) | NA | 8/46 | 9/10 | 6/21 | – |
| Anticonvulsants (yes/no) | NA | 4/50 | 1/18 | 0/27 | – |
| Benzodiazepine | NA | 1/53 | 2/17 | 5/22 | – |
| Chronic disease (yes/no) | NA | 11/8 | 16/38 | 20/7 | 0.00 |
| Hypertension (yes/no) | NA | 14/40 | 10/9 | 14/13 | – |
| Diabetes mellitus (yes/no) | NA | 5/49 | 1/18 | 4/23 | – |
| Asthma (yes/no) | NA | 1/53 | 3/16 | 3/24 | – |
| Number of analgesic doses used per week (≥4 doses-week/<4 doses) | NA | 27/26 | 14/5 | 20/6 | 0.04 |
| Pain on the VAS (last 7 days) | NA | 7.23 (2.19) | 7.94 (1.89) | 6.26 (2.15) | 0.03 |
| Pain on the VAS (24 h) | NA | 6.11 (2.59) | 7.10 (1.88) | 5.37 (2.47) | 0.06 |
| Beck depression inventory II | NA | 13.92 (8.85) | 24.47 (11.67) | 10.04 (7.18) | 0.00 |
| Brazilian portuguese catastrophizing scale (B-PCS) | NA | 28.26 (12.51) | 34.68 (11.69) | 22.89 (11.59) | 0.00 |
| Serum BDNF (ng/mL) | 19.00 (8.79) | 29.28 (20.01) | 50.78 (16.06) | 17.91 (7.27) | 0.00 |
Data are presented as mean (standard deviation) or number of subjects (n = 114). *Patients could have none or more than one psychiatric disorder. **Some patients were using more than one type of drug. Abbreviations: visual analog scale for pain, from 0 to 10 (VAS); brain-derived neurotrophic factor (BDNF).