Parameters that were selected in phase I, and frequencies of these parameters in the patients that in phase II were categorised as CSA, no-CSA or were considered unclassifiable
| No-CSA (n=17) (%) | Unclassifiable (n=19) (%) | CSA (n=14) (%) | |
|---|---|---|---|
| History taking | |||
| Joint symptoms of recent onset (duration <1 year) | 41 | 74 | 92 |
| 4–10 joints with symptoms | 47 | 57 | 21 |
| Symptoms in MCP joints | 35 | 63 | 93 |
| Symptoms in MTP joints | 35 | 53 | 57 |
| Symptoms in several small joint regions (MCP, wrists, PIP, MTP joints) | 35 | 68 | 93 |
| Symmetric symptoms or signs (bilateral in same joint region) | 77 | 58 | 100 |
| Duration of morning stiffness ≥60 min | 6 | 37 | 71 |
| Most severe symptoms in the early morning | 27 | 69 | 90 |
| Improvement of symptoms during the day | 15 | 36 | 90 |
| Increasing number of joints with symptoms over time | 70 | 71 | 90 |
| Patient experience of swelling of small hand joints | 31 | 47 | 77 |
| Presence of a first-degree relative with RA | 7 | 33 | 36 |
| Physical examination | |||
| Difficulty with making a fist | 8 | 31 | 43 |
| Local tenderness involved joints at physical examination | 63 | 84 | 86 |
| Positive squeeze test of MCP joints | 14 | 26 | 69 |
| Positive squeeze test of MTP joints | 22 | 21 | 39 |
Data on symptoms of recent onset was missing in 1 patient, on most severe symptoms in early morning in 6 patients, on improvement of symptoms during the day in 8 patients, on increasing number of joints with symptoms over time in 11 patients, on patient experience of swelling in 2 patients, on difficulty with making a fist, presence of a first-degree relative with RA, local tenderness of joints, squeeze test of MCP and MTP joints in 4 patients.
CSA, clinically suspect arthralgia; MCP, metacarpophalangeal; MTP, metatarsophalangeal; PIP, proximal interphalangeal; RA, rheumatoid arthritis.