Table 1.
Socio-demographic and disease-related characteristics of JIA patients according to the time when biologic was started
| Total | bDMARD started < 2 years after disease onset | bDMARD started 2–5 years after disease onset | bDMARD started > 5 years after disease onset | p-value | |
|---|---|---|---|---|---|
| Patients, n (%) | 361 (100) | 52 (14.4) | 65 (18) | 244 (67.5) | |
| Female, n (%) | 194 (53.7) | 19 (36.5) | 21 (32.3) | 154 (63.1)c | 0.015* |
| JIA ILAR category, n (%) | 0.001** | ||||
| Persistent oligoarthritis | 33 (9.1) | 2 (3.8) | 12 (18.5) | 19 (7.8) | |
| Extended oligoarthritis | 58 (16.1) | 7 (13.5) | 8 (12.3) | 43 (17.6) | |
| RF-positive polyarthritis | 39 (10.8) | 3 (5.8) | 4 (6.2) | 32 (13.1) | |
| RF-negative polyarthritis | 70 (19.4) | 10 (19.2) | 11 (16.9) | 49 (20.1) | |
| Systemic | 34 (9.4) | 5 (9.6) | 8 (12.3) | 21 (8.6) | |
| Enthesitis related arthritis | 88 (24.4) | 22 (42.3) | 16 (24.6) | 50 (20.5) | |
| Psoriatic arthritis | 17 (4.7) | 3 (5.8) | 4 (6.2) | 10 (4.1) | |
| Undifferentiated arthritis | 22 (6.4) | 0 (0) | 3 (4.6) | 19 (7.8) | |
| Age at disease onset, years, median (IQR) | 11.5 (6.3–14.6) | 13.3 (11.7–15.7)a | 12.2 (9.8–14.7)b | 9.8 (5.3–14)a,b | < 0.001* |
| Age at diagnosis, years, median (IQR) | 13.3 (8.2–16.8) | 13.1 (10.4–16.1) | 13.0 (10.6–15.7) | 13.2 (6.8–18.2) | 0.392 |
| Age when first biologic was started, years, median (IQR) | 21.7 (15.8–31.9) | 15.3 (13.4–16.4)a | 15.8 (13–17.9)b | 26.3 (19.7–36)a,b | < 0.001* |
| Disease duration, years, median (IQR) | 20.3 (12.1–30.2) | 7.5 (3.8–11.6)a | 10.8 (6.4–15.9)b | 25.1 (19.3–34.1)a,b | < 0.001* |
| Age at last visit, years, median (IQR) | 29.1 (21.8–40.2) | 20.2 (18.9–23.2)a | 21.9 (19.7–25.5)b | 35.5 (27–44.8)a,b | < 0.001* |
| ANA + , n assessed: 225, n (%) | 71 (31.5) | 9 (21.4) | 11 (25.6) | 51 (36.4)c | 0,003* |
| RF + , n assessed: 267, n (%) | 73 (27.3) | 8 (20) | 5 (11.1) | 60 (33)c | 0.032* |
| ACPA + , n assessed: 175, n (%) | 47 (26.8) | 7 (22.5) | 3 (10.3) | 37 (32.2) | 0.271 |
| HLAB27 + , n assessed: 183, n (%) | 78 (42.6) | 17 (48.6) | 14 (45.2) | 47 (40.2) | 0.164 |
| Presence of uveitis, n assessed: 285, n (%) | 40 (14) | 2 (5) | 9 (20) | 29 (14.5) | 0.105 |
| Years of education, n assessed: 203; median (IQR) | 12 (9–15) | 11 (9–12) | 11 (9–14) | 12 (9–15)c | 0.24 |
| Professional situation, n assessed: 210 | 0.193 | ||||
| Employed, n (%) | 159 (75.7) | 18 (60)c | 21 (63.6) c | 120 (81.6) | |
| Unemployed, n (%) | 18 (8.6) | 0 (0) | 1 (3) | 17 (11.6)c | |
| Retired, n (%) | 7 (3.3) | 0 (0) | 0 (0) | 7 (4.8)c | |
| Retired due to JIA disability, n (%) | 17 (8.1) | 0 (0) | 0 (0) | 17 (11.6)c | |
| Past treatment | |||||
| Corticosteroids, n (%) | 181 (50.1) | 21 (40.4) | 15 (23.1) | 145 (59.4)c | 0.002 |
| cDMARDs, n (%) | 280 (77.6) | 34 (65.4) | 38 (58.5) | 208 (85.2) | 0.709 |
| Current treatment | |||||
| Corticosteroids, n assessed: 271, n (%) | 88 (32.5) | 4 (14.3) | 3 (7.3) | 81 (40.1)c | < 0,001 |
| cDMARDs, n assessed: 272, n (%) | 159 (58.5) | 13 (44.8) | 15 (36.6) | 129 (63.9) | 0.148 |
| bDMARDS, n (%) | 295 (81.7) | 33 (63.5) | 36 (55.4) | 196 (80.3) | 0.817 |
| Cumulative corticosteroid exposure, years, median (IQR) | 5.9 (2.4–14.9) | 1.8 (0.8–2.3)a | 3.9 (1.9–8.2) | 7.8 (2.9–17.1]a | < 0.001* |
Sample size is not constant due to missing data:
Patients whose bDMARD was started < 2 years after disease onset: ANA + n = 42; RF + n = 40; ACPA + n = 31; HLAB27 + n = 35; presence of uveitis n = 40; professional situation n = 30; current corticosteroids n = 28; current cDMARDs n = 29
Patients whose bDMARD was started 2–5 years after disease onset: ANA + n = 43; RF + n = 45; ACPA + n = 29; HLAB27 + n = 31; presence of uveitis n = 45; professional situation n = 33; current corticosteroids n = 41; current cDMARDs n = 41
Patients whose bDMARD was started > 5 years after disease onset: ANA + n = 140; RF + n = 182; ACPA + n = 115; HLAB27 + n = 117; presence of uveitis n = 200; professional situation n = 147; current corticosteroids n = 202; current cDMARDs n = 202
Legend: JIA juvenile idiopathic arthritis, IQR interquartile range, ANA antinuclear antibodies, RF rheumatoid factor, ACPA anti-citrullinated protein antibodies, DMARD disease-modifying antirheumatic drugs, cDMARDs conventional DMARD, bDMARDs biological DMARDs
aStatistically significant difference between “ < 2Y” and “ > 5Y” at a 5% significance level — Mann–Whitney U test adjusted for multiple comparisons
bStatistically significant difference between “2–5Y” and “ > 5Y” ate a 5% significance level — Mann–Whitney U test adjusted for multiple comparisons
cHigher frequency than expected (statistically significant at a 5% significance level — Fisher exact test and adjusted residual higher than 1.96)
*Statistically significant difference between “ < 5Y” and “ ≥ 5Y” at a 5% significance level — Mann–Whitney U test
**Fisher exact test applied using “Extended oligoarthritis,” “RF-positive polyarthritis,” and “RF-negative polyarthritis” categories of JIA grouped as one in order to perform the test with some robustness