Journal of Rheumatic Diseases

Table. 1.

Baseline characteristics of the study subjects with respect to the shared epitope

Variable All (n=533) Shared epitope p-value
Negative (n=204) Positive (n=329)
Female 428 (80.3) 173 (84.8) 255 (77.5) 0.052
Age at diagnosis (yr) 50 (41, 59) 48 (40, 60) 50 (42, 59) 0.536
BMI 0.203
Underweight 36 (6.8) 11 (5.4) 25 (7.6)
Normal 379 (71.1) 148 (72.5) 231 (70.2)
Overweight 101 (18.9) 35 (17.2) 66 (20.1)
Obese 17 (3.2) 10 (4.9) 7 (2.1)
Smoking* 117 (22.0) 40 (19.6) 77 (23.4) 0.357
Diabetes 70 (13.1) 28 (13.7) 42 (12.8) 0.852
Hypertension 197 (37.0) 70 (34.3) 127 (38.6) 0.366
Dyslipidemia 274 (51.4) 107 (52.5) 167 (50.8) 0.771
ESR (mm/h) 45 (26, 69) 42 (26, 68) 46 (26, 70) 0.575
CRP (mg/dL) 0.8 (0.2, 2.3) 0.6 (0.2, 2.0) 1.0 (0.3, 2.9) 0.005
IgM RF
Positive 474 (88.9) 180 (88.2) 294 (89.4) 0.794
Titer (IU/mL) 70.9 (29.7, 184.0) 77.9 (30.8, 199.8) 70.7 (28.8, 175.7) 0.811
Subgroup 0.899
Negative 59 (11.1) 24 (11.1) 35 (10.6)
Low to moderate 348 (65.3) 93 (45.6) 155 (47.1)
High 137 (25.7) 87 (42.6) 139 (42.2)
ACPA
Positive 485 (91.0) 179 (87.7) 306 (93.0) 0.056
Titer (IU/mL) 100.0 (30.9, 200.0) 95.2 (22.1, 200.0) 100.0 (35.2, 200.0) 0.177
Subgroup 0.105
Negative 48 (9.0) 25 (12.3) 23 (7.0)
Low to moderate 348 (65.3) 126 (61.8) 222 (67.5)
High 137 (25.7) 52 (26.0) 84 (25.5)
SHS (units) 0 (0, 7) 0 (0, 4) 0 (0, 10) 0.020
Erosion 72 (13.5) 19 (9.3) 53 (16.1) 0.035
DAS28-CRP (units) 3.9 (3.4, 4.3) 3.9 (3.3, 4.3) 3.9 (3.5, 4.3) 0.220
Bone mineral density
L-spine 0.132
Normal 286 (53.7) 119 (58.3) 167 (50.8)
Osteopenia 116 (21.8) 44 (21.6) 72 (21.9)
Osteoporosis 131 (24.6) 41 (20.1) 90 (27.4)
Femur 0.361
Normal 224 (42.0) 93 (45.6) 131 (39.8)
Osteopenia 248 (46.5) 91 (44.6) 157 (47.7)
Osteoporosis 61 (11.4) 20 (9.8) 41 (12.5)
Osteoporosis 148 (27.8) 46 (22.5) 102 (31.0) 0.044
bDMARDs or tsDMARDs 216 (40.5) 71 (34.8) 145 (44.1) 0.043

Values are presented as number (%) or median (interquartile range). ACPA: anti-cyclic citrullinated protein antibody, BMI: body mass index, CRP: C-reactive protein, DMARD: disease-modifying anti-rheumatic disease, ESR: erythrocyte sedimentation rate, RF: rheumatoid factor, SHS: van der Heijde modified Sharp score, DAS28: disease activity score in 28 joints. *Include ex- and current smokers. Biologic DMARDs (bDMARDs) include tumor necrosis factor inhibitors (etanercept, adalimumab, infliximab, golimumab), tocilizumab, abatacept, and rituximab. Targeted synthetic DMARDs (tsDMARDs) include tofacitinib and baricitinib. When adjusted by sex and onset age, p-value was 0.194 (odds ratio [95% confidence interval] 1.0052 [0.9972~1.0134]).

J Rheum Dis 2022;29:171~180 https://doi.org/10.4078/jrd.2022.29.3.171
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