Table 1. The main demographic and clinical characteristics of patients and controls.
| Characteristics | Case | Control | P value |
|---|---|---|---|
| Age, mean±SD (years) | 54.4±12.3 | 55.1±9.8 | 0.953 |
| Female(%)/Male(%) | 76.6/23.4 | 75.0/25.0 | 0.731 |
| Age at onset, mean±SD (years) | 43.9±14.4 | - | - |
| Disease duration, mean±SD (years) | 10.5±9.9 | - | - |
| DAS28, mean±SD | 6.32±1.62 | - | - |
| RF-positive (%) | 84.81 | - | - |
| AntiCCP-positive (%) | 83.54 | - | - |
| AKA-positive (%) | 45.95 | - | - |
| CRP,mean±SD (%) | 34.8±43.5 | - | - |
| ESR, mean±SD (mm/h) | 70.5±34.6 | - | - |
Note: a) Data were expressed as median ± SD or median (interquartile range).
b)-: data were not available.
Abbreviations: DAS28, disease activity score for 28 painful/swollen joints; RF, rheumatoid factor; AntiCCP, anti-cyclic citrullinated peptide; CRP, c-reactive protein; AKA, anti-keratin antibody; ESR, erythrocyte sedimentation rate.