Table 2.
Baseline characteristics and follow-up data on non-biological DMARD use of biological therapy-naive patients and patients who started to use biological therapy
| Cohort 1 | Cohort 2 | |||
|---|---|---|---|---|
| Biological therapy-naive group (n=375) | Biological therapy group (n=32) | Biological therapy-naive group (n=371) | Biological therapy group (n=45) | |
| Age at symptom onset (years) | 54 (44–65) | 47 (35–55) | 58 (48–70) | 50 (41–55) |
| Gender (female) | 224 (60%) | 26 (81%) | 232 (63%) | 37 (82%) |
| Baseline characteristics | ||||
| Symptom duration (months) | 5.4 (3.0–9.7) | 5.4 (3.3–12.9) | 6.7 (4.4–11.7) | 6.4 (4.6–8.7) |
| RA (1987 ACR criteria) | 230 (61.3%) | 25 (78.1%) | 194 (52.3%) | 26 (57.8%) |
| No of swollen joints | 8 (2–14) | 5 (3–12) | 3 (1–7) | 4 (1–7) |
| No of tender joints | 7 (2–14) | 5 (2–10) | 3 (0–8) | 5 (1–8) |
| CRP (mg/L) | 10 (2–27) | 10 (4–23) | 12 (4–25) | 16 (3–36) |
| DAS28(3)CRP | 4.5 (3.5–5.5) | 4.3 (3.2–5.4) | 3.7 (2.8–4.6) | 4.4 (3.0–5.0) |
| HAQ score | 1 (0.5–1.6) | 1.1 (0.5–1.5) | 1.0 (0.5–1.6) | 1.1 (0.4–1.9) |
| RF (positive) | 142 (42.0%) | 18 (60.0%) | 139 (41.5%) | 16 (44.4%) |
| ACPA (positive) | 113 (42.3%) | 17 (81.0%) | 110 (36.2%) | 26 (70.3%) |
| SE | ||||
| 0 allele | 108 (33.6%) | 7 (23.3%) | 127 (38.5%) | 8 (19.5%) |
| 1 allele | 157 (48.9%) | 13 (43.3%) | 154 (46.7%) | 24 (58.5%) |
| 2 alleles' | 56 (17.5%) | 10 (33.3%) | 49 (14.9%) | 9 (22.0%) |
| Smoking | ||||
| Never smoked | 116 (30.9%) | 13 (40.6%) | 104 (31.3%) | 9 (20.0%) |
| Ex-smoker | 153 (40.8%) | 9 (28.1%) | 149 (44.9%) | 17 (37.8%) |
| Current smoker | 106 (28.3%) | 10 (31.3%) | 79 (23.8%) | 19 (42.2%) |
| Follow-up data | ||||
| Follow-up duration (months) | 168 (96–186) | 188 (182–193) | 68 (60–88) | 70 (64–91) |
| Time until starting first DMARD since symptom onset (months) | 9 (4–19) | 10 (5–16) | 6 (4–12) | 7 (4–8) |
| Time until starting first biological therapy since symptom onset (months) | 143 (118–159) | 47 (24–69) | ||
| First prescribed biological therapy | ||||
| Etanercept | 11 (34%) | 12 (27%) | ||
| Infliximab | 14 (44%) | 10 (22%) | ||
| Adalimumab | 6 (19%) | 23 (51%) | ||
| Rituximab | 1 (3%) | 0 | ||
| No of non-biological DMARD before start first biological therapy | 3.3 (1.4) | 3.0 (1.3) | ||
| Used steroids before starting biological agent (yes) | 21 (66%) | 23 (51%) | ||
Patients in cohort 1 were recruited between 1990 and 1994 and patients in cohort 2 were recruited between 2000 and 2004. Values are median (IQR) or mean (SD) for continuous variables and numbers (%) for categorical variables.
ACPA, anti-citrullinated protein antibody; ACR, American College of Rheumatology; CRP, C-reactive protein; DAS28(3)CRP, 28-joint disease activity score based on three components including CRP; DMARD, disease-modifying antirheumatic drug; HAQ, health assessment questionnaire; RA, rheumatoid arthritis; RF, rheumatoid factor; SE, shared epitope.