Table 1.
Demographics and clinical characteristics of subjects.
| Variables | Total (n = 424) | Non-frailty (n = 245) | Frailty (n = 179) | p value |
|---|---|---|---|---|
| Age (years), mean (SD) | 66.8(14.5) | 62.7 (14.5) | 72.4 (12.7) | < 0.001 |
| Duration of disease (years), mean (SD) | 13.0 (10.6) | 12.0 (10.1) | 14.3 (11.2) | 0.023 |
| BMI (kg/m2), mean (SD) | 21.6 (3.8) | 21.4 (3.8) | 21.8 (3.9) | 0.280 |
| Married (%) | 61.3 | 66.5 | 54.2 | 0.012 |
| Living alone (%) | 17.0 | 16.3 | 17.9 | 0.696 |
| Education ≥ 13 years (%) | 30.0 | 34.3 | 24.0 | 0.024 |
| Steinbrocker stage (3/4) (%) | 40.8 | 35.8 | 47.5 | 0.020 |
| Steinbrocker class (3/4) (%) | 15.6 | 4.6 | 30.5 | < 0.001 |
| Glucocorticoid use (%) | 31.4 | 24.9 | 40.2 | 0.001 |
| Methotrexate use (%) | 65.6 | 72.7 | 55.9 | < 0.001 |
| Other csDMARD use (%) | 42.7 | 41.2 | 44.7 | 0.488 |
| bDMARD or tsDMARD use (%) | 39.2 | 37.1 | 41.9 | 0.365 |
| Diabetes mellitus (%) | 7.3 | 4.9 | 10.6 | 0.036 |
| Hypertension (%) | 18.4 | 12.2 | 26.8 | < 0.001 |
| Osteoporosis (%) | 30.9 | 21.6 | 43.6 | < 0.001 |
| Interstitial pneumonia (%) | 9.7 | 7.3 | 12.8 | 0.068 |
| Ever or current malignancy (%) | 7.8 | 5.3 | 11.2 | 0.029 |
| Rheumatoid factor positive (%) | 72.1 | 71.1 | 73.6 | 0.656 |
| CRP (mg/dl), mean (SD) | 0.4 (1.2) | 0.3 (0.6) | 0.6 (1.7) | 0.011 |
| MMP-3 (ng/ml), mean (SD) | 86.2 (98.4) | 78.3 (91.0) | 97.1 (107.0) | 0.056 |
| Swollen 28-joint count, mean (SD) | 0.8 (2.0) | 0.7 (1.6) | 0.9 (2.4) | 0.178 |
| Tender 28-joint count, mean (SD) | 2.1 (3.8) | 1.3 (2.3) | 3.2 (5.1) | < 0.001 |
| Subject's assessment of pain VAS (mm), mean (SD) | 20.5 (23.5) | 14.2 (18.9) | 29.1 (26.3) | < 0.001 |
| Subject's global assessment of disease activity VAS (mm), mean (SD) | 20.8 (22.9) | 14.4 (18.5) | 29.6 (25.3) | < 0.001 |
| Physician's global assessment of disease activity VAS (mm), mean (SD) | 17.7 (20.4) | 12.0 (15.8) | 25.6 (23.2) | < 0.001 |
| DAS28-CRP, mean (SD) | 2.3 (1.0) | 2.0 (0.9) | 2.6 (1.1) | < 0.001 |
| HAQ-DI, mean (SD) | 0.54 (0.76) | 0.20 (0.36) | 1.01 (0.90) | < 0.001 |
| KCL, mean (SD) | 7.2 (4.8) | 3.8 (2.0) | 11.9 (3.5) | < 0.001 |
| Dominant side (right/left/equal) (%) | 45.1/35.6/19.3 | 47.8/34.3/18.0 | 41.3/37.4/21.2 | 0.401 |
| Grip strength (kg), mean (SD) | 17.4 (7.4) | 19.7 (6.6) | 14.1 (7.4) | < 0.001 |
| Finger/wrist joint symptoms (%) | 35.4 | 30.2 | 42.5 | 0.010 |
Frailty, The Kihon Checklist (KCL) ≥ 8 points.
BMI body mass index, other csDMARD conventional synthetic disease-modifying antirheumatic drug (DMARD) including salazosulfapyridine, tacrolimus, bucillamine, and iguratimod, bDMARD biological DMARD, tsDMARD targeted synthetic DMARD, CRP C-reactive protein, MMP-3 matrix metalloproteinase-3, VAS visual analog scale, DAS28-CRP 28-joint count Disease Activity Score using C-reactive protein, HAQ-DI Health Assessment Questionnaire-Disability Index, dominant side side with the higher value of grip strength, SD standard deviation.