Relative frequency of recognition criteria C1–C4 in the cohorts referred to the rheumatologist (n=670)
| Cohort | C1 | C2 | C3 | C4 | Frequency |
|---|---|---|---|---|---|
| 1 | – | – | – | – | 21 (3.1%) |
| 2 | ■ | – | – | – | 17 (2.5%) |
| 3 | – | ■ | – | – | 50 (7.5%) |
| 4 | – | – | ■ | – | 26 (3.9%) |
| 5 | – | – | – | ■ | 46 (6.9%) |
| 6 | ■ | ■ | – | – | 27 (4.0%) |
| 7 | ■ | – | ■ | – | 8 (1.2%) |
| 8 | ■ | – | – | ■ | 19 (2.8%) |
| 9 | – | ■ | ■ | – | 100 (14.9%) |
| 10 | – | ■ | – | ■ | 93 (13.9%) |
| 11 | – | – | ■ | ■ | 34 (5.1%) |
| 12 | ■ | ■ | ■ | – | 39 (5.8%) |
| 13 | ■ | ■ | – | ■ | 29 (4.3%) |
| 14 | ■ | – | ■ | ■ | 14 (2.1%) |
| 15 | – | ■ | ■ | ■ | 94 (14.0%) |
| 16 | ■ | ■ | ■ | ■ | 53 (7.9%) |
Prespecified recognition criteria: C1, morning stiffness >30 min; C2, improvement by movement not by rest; C3, waking up in the second half of the night because of back pain; C4, improvement with non-steroidal anti-inflammatory drugs within 48 h.The filled boxes indicate that these items were present, the bars indicate absence.