Table 3. Predictors of RA development and/or treatment intensification in ACPA-negative undifferentiated arthritis—univariable analysis.
| RA development | RA development/Treatment intensification | |||||
|---|---|---|---|---|---|---|
| OR | 95% CI | P value | OR | 95% CI | P value | |
| Demographics | ||||||
| Age | 1.00 | 0.98 to 1.02 | 0.86 | 1.00 | 0.98 to 1.01 | 0.64 |
| Age (years) | ||||||
| ≤44 | ref | ref | ||||
| 45–64 | 0.99 | 0.47 to 2.10 | 0.98 | 1.20 | 0.70 to 2.04 | 0.51 |
| ≥65 | 0.79 | 0.32 to 1.94 | 0.61 | 0.87 | 0.47 to 1.62 | 0.67 |
| Female gender | 1.32 | 0.63 to 2.79 | 0.46 | 0.94 | 0.58 to 1.54 | 0.81 |
| Symptom history | ||||||
| Symptoms duration | 0.99 | 0.98 to 1.01 | 0.30 | 1.00 | 0.99 to 1.00 | 0.33 |
| Symptoms duration <12 weeks | 0.68 | 0.30 to 1.56 | 0.36 | 0.85 | 0.49 to 1.47 | 0.56 |
| Stiffness ≥30 min | 0.60 | 0.25 to 1.47 | 0.27 | 0.94 | 0.51 to 1.76 | 0.86 |
| Stiffness ≥60 min | 0.76 | 0.38 to 1.53 | 0.44 | 0.86 | 0.54 to 1.41 | 0.58 |
| Joint phenotype | ||||||
| Swollen large joint | 1.84 | 0.92 to 3.65 | 0.08 | 2.51 | 1.47 to 4.30 | <0.001*** |
| Swollen hand | 3.74 | 0.49 to 28.68 | 0.20 | 0.89 | 0.36 to 2.18 | 0.80 |
| MTP squeeze | 0.82 | 0.10 to 6.73 | 0.85 | 0.40 | 0.08 to 1.92 | 0.25 |
| Hand | ref | ref | ||||
| Large | 0.40 | 0.05 to 3.08 | 0.38 | 1.54 | 0.63 to 3.81 | 0.35 |
| Hand+large | 2.49 | 1.24 to 5.00 | 0.01* | 2.93 | 1.67 to 5.15 | <0.001*** |
| Monarthritis | ref | ref | ||||
| Oligoarthritis | 0.92 | 0.46 to 1.85 | 0.81 | 0.92 | 0.57 to 1.49 | 0.74 |
| Polyarthritis | 1.77 | 0.57 to 5.49 | 0.33 | 1.63 | 0.67 to 3.98 | 0.28 |
| Symmetric involvement | 1.20 | 0.62 to 2.33 | 0.59 | 1.41 | 0.90 to 2.22 | 0.14 |
| Joint counts | ||||||
| SJC28 | 1.12 | 0.97 to 1.30 | 0.11 | 1.04 | 0.93 to 1.16 | 0.54 |
| SJC44 | 1.05 | 0.93 to 1.19 | 0.43 | 1.02 | 0.93 to 1.11 | 0.74 |
| TJC28 | 1.00 | 0.94 to 1.07 | 0.97 | 1.00 | 0.96 to 1.04 | 0.99 |
| TJC46 | 1.00 | 0.96 to 1.04 | 0.90 | 1.01 | 0.98 to 1.03 | 0.70 |
| Patient-reported | ||||||
| VAS pain | 1.02 | 0.99 to 1.03 | 0.06 | 1.01 | 1.00 to 1.02 | 0.02* |
| PGA | 1.01 | 0.99 to 1.02 | 0.50 | 1.01 | 0.99 to 1.02 | 0.37 |
| HAQ | 1.29 | 0.63 to 2.64 | 0.49 | 0.92 | 0.54 to 1.56 | 0.75 |
| Laboratory and imaging | ||||||
| ESR | 1.00 | 0.98 to 1.02 | 0.84 | 1.00 | 0.99 to 1.02 | 0.56 |
| ESR >15 | 0.98 | 0.50 to 1.88 | 0.92 | 1.17 | 0.74 to 1.84 | 0.50 |
| CRP | 1.03 | 0.77 to 1.39 | 0.82 | 1.26 | 1.01 to 1.58 | 0.04* |
| CRP >0.5 | 1.68 | 0.89 to 3.19 | 0.11 | 1.89 | 1.20 to 2.98 | 0.006** |
| RF | 1.11 | 0.24 to 5.14 | 0.89 | 0.64 | 0.20 to 2.08 | 0.46 |
| ANA | 1.01 | 0.52 to 1.98 | 0.98 | 1.09 | 0.68 to 1.74 | 0.72 |
| SHS erosion score ≥1 | 1.06 | 0.35 to 3.19 | 0.92 | 0.99 | 0.45 to 2.17 | 0.98 |
*p<0.5 **p<0.01 ***p<0.001
ACPA, anticitrullinated protein autoantibodies; ANA, antinuclear antibodies; CRP, C reactive protein; ESR, erythrocyte sedimentation rate; HAQ, Health Assessment Questionnaire; MTP, metatarsophalangeal joints; PGA, Patient Global Assessment; RA, rheumatoid arthritis; ref, reference; RF, rheumatoid factor; SHS, Sharp van der Heijde Score; SJC, swollen joint count; TJC, tender joint count; VAS, visual analogue scale.