Table 1.
Demographic and clinical characteristics of patients with rheumatoid arthritis by season in NinJa2016
| Total | Spring | Summer | Fall | Winter | p-value# | |
|---|---|---|---|---|---|---|
| n = 12,839 | n = 3250 | n = 916 | n = 1021 | n = 7652 | ||
| Age (years) | 65.2 ± 12.9 | 65.3 ± 13.1 | 65.5 ± 13.2 | 65.4 ± 12.8 | 65.1 ± 12.9 | 0.649 |
| Female (%) | 10,287 (80.1%) | 2600 (80.0%) | 746 (81.4%) | 825 (80.8%) | 6166 (79.9%) | 0.680 |
| Disease duration (years) | 13.4 ± 11.0 | 13.4 ± 11.2 | 13.9 ± 11.4 | 14.2 ± 10.8 | 13.2 ± 10.9 | 0.026 |
| Stage III–IV (%) | 5917 (46.1%) | 1456 (44.8%) | 451 (49.2%) | 481 (47.1%) | 3529 (46.1%) | 0.100 |
| Class 3–4 (%) | 2412 (18.8%) | 613 (18.9%) | 162 (17.7%) | 153 (15.0%) | 1484 (19.4%) | 0.007 |
| TJC | 1.9 ± 4.2 | 2.0 ± 4.1 | 1.4 ± 3.4 | 1.6 ± 3.9 | 2.0 ± 4.3 | < 0.001 |
| SJC | 1.4 ± 2.7 | 1.8 ± 3.3 | 1.4 ± 2.7 | 1.0 ± 2.3 | 1.3 ± 2.5 | < 0.001 |
| Pain (cm) | 2.4 ± 2.3 | 2.4 ± 2.3 | 2.5 ± 2.3 | 2.3 ± 2.2 | 2.4 ± 2.2 | 0.463 |
| PGA (cm) | 2.5 ± 2.2 | 2.5 ± 2.2 | 2.6 ± 2.3 | 2.4 ± 2.2 | 2.5 ± 2.2 | 0.332 |
| PhGA (cm) | 1.5 ± 1.4 | 1.5 ± 1.5 | 1.4 ± 1.4 | 1.2 ± 1.3 | 1.5 ± 1.4 | < 0.001 |
| mHAQ | 0.39 ± 0.61 | 0.41 ± 0.63 | 0.40 ± 0.62 | 0.38 ± 0.58 | 0.38 ± 0.61 | 0.126 |
| CRP (mg/dL) | 0.55 ± 1.21 | 0.56 ± 1.26 | 0.58 ± 1.14 | 0.55 ± 1.22 | 0.55 ± 1.20 | 0.854 |
#Chi-square tests were used for categorical variables and analysis of variance tests for continuous variables. TJC tender joint count, SJC swollen joint count, PGA patient global assessment of RA disease activity, PhGA physician global assessment of RA disease activity, VAS visual analog scale, CRP C-reactive protein, mHAQ modified Health Assessment Questionnaire