Table 1.
Comparisons of baseline characteristics and therapeutic response between CDAI50 responders and non-responders
| Total (n = 510) | CDAI50 respondersa (n = 328) | Non-respondersa (n = 182) | OR (95% CI)b | |
|---|---|---|---|---|
| Baseline characteristics | ||||
| Age, years, mean (95% CI) | 62.8 (61.7, 63.9) | 62.5 (61.1, 64.0) | 63.4 (61.7, 65.0) | 1.00 (0.98, 1.01) |
| Male/female | 109/401 | 61/267 | 48/134 | 0.64 (0.41, 0.98) |
| RA duration, months, mean (95% CI) | 117.2 (107.3, 127.0) | 109.0 (97.2, 120.8) | 131.9 (114.2, 149.5) | 0.99 (0.99, 1.00) |
| Radiographic stages III/IV, number (%) | 309 (60.6) | 191 (58.2) | 118 (64.8) | 0.76 (0.52, 1.10) |
| Anti-CCP (+), number (%) | 439 (86.1) | 288 (87.8) | 151 (83.0) | 1.48 (0.89, 2.46) |
| CDAI at the start of TCZ treatment, mean (95% CI) | 24.7 (23.7, 25.6) | 26.0 (24.7, 27.2) | 22.3 (21.0, 23.7) | 1.03 (1.02, 1.05) |
| High CDAI (CDAI > 22), number (%) | 254 (49.8) | 180 (54.9) | 74 (40.7) | 1.78 (1.23, 2.56) |
| Failure of previous RA treatmentc, number (%) | 373 (73.1) | 240 (73.2) | 133 (73.1) | 1.01 (0.67, 1.51) |
| Previous use of biological DMARDs, number (%) | 287 (56.3) | 176 (53.7) | 111 (61.0) | 0.74 (0.51, 1.07) |
| Concurrent use of MTX, number (%) | 273 (53.5) | 174 (53.0) | 99 (54.4) | 0.95 (0.66, 1.36) |
| Dose, mg/week, mean (95% CI) | 8.9 (8.6, 9.2) | 8.9 (8.5, 9.2) | 8.9 (8.4, 9.5) | 0.98 (0.89, 1.08) |
| Concurrent use of other csDMARDsd, number (%) | 150 (29.4) | 93 (28.4) | 57 (31.3) | 0.87 (0.59, 1.29) |
| Concurrent use of prednisolone, number (%) | 218 (42.7) | 135 (41.2) | 83 (45.6) | 0.83 (0.58, 1.20) |
| Dose, mg/day, mean (95% CI) | 5.8 (5.4, 6.3) | 5.9 (5.3, 6.5) | 5.7 (5.1, 6.4) | 1.01 (0.95, 1.08) |
| Hypertension, number (%) | 187 (36.7) | 116 (35.4) | 71 (39.0) | 0.86 (0.59, 1.24) |
| Type 2 diabetes, number (%) | 75 (14.7) | 49 (14.9) | 26 (14.3) | 1.05 (0.63, 1.76) |
| CKD, number (%) | 98 (19.2) | 61 (18.6) | 37 (20.3) | 0.90 (0.57, 1.41) |
| Year of TCZ initiation (since 2012), number (%) | 308 (60.4) | 196 (59.8) | 112 (61.5) | 0.93 (0.64, 1.35) |
| CDAI at 6 monthse, mean (95% CI) | 10.4 (9.6, 11.2) | 7.9 (7.2, 8.7) | 14.8 (13.2, 16.4) | 0.91 (0.89, 0.93) |
| CDAI85 (major response), number (%) | 102 (20) | 91 (27.7) | 11 (6.0) | 5.97 (3.10, 11.50) |
| CDAI70 (moderate response), number (%) | 194 (38.0) | 173 (52.7) | 21 (11.5) | 8.56 (5.17, 14.17) |
| High and moderate CDAI (CDAI > 10), number (%) | 221 (43.3) | 90 (27.4) | 131 (72.0) | 0.23 (0.16, 0.34) |
| Remission (CDAI ≤ 2.8), number (%) | 83 (16.3) | 74 (22.6) | 9 (4.9) | 5.60 (2.73, 11.49) |
| CDAI50 response, number (%) | 320 (62.7) | 272 (82.9) | 48 (26.4) | 13.6 (8.8, 21.0) |
| MCID-based CDAI improvement, number (%) | 315 (61.8) | 287 (87.5) | 28 (15.4) | 38.5 (22.9, 64.7) |
| CDAI at 12 monthse, mean (95% CI) | 9.0 (8.2, 9.7) | 5.0 (4.6, 5.4) | 16.1 (14.5, 17.6) | 0.75 (0.71, 0.79) |
| CDAI85 (major response), number (%) | 135 (26.5) | 135 (41.2) | 0 | — |
| CDAI70 (moderate response), number (%) | 245 (48.0) | 245 (74.7) | 0 | — |
| High and moderate CDAI (CDAI > 10), number (%) | 188 (36.9) | 26 (7.9) | 162 (89.0) | — |
| Remission (CDAI ≤ 2.8), number (%) | 107 (21.0) | 107 (32.6) | 0 | — |
| MCID-based CDAI improvement, number (%) | 341 (66.9) | 325 (99.1) | 16 (8.8) | — |
aCDAI50 responders were defined as patients who had achieved and maintained a CDAI50 response during the first 12 months of TCZ treatment.
bORs (95% CI) are presented for CDAI50 responders compared with non-responders based on binominal logistic regression analysis. For continuous data, ORs are shown per 1 year more of age, 1 month more of RA duration, 1 mg more of MTX and prednisolone, and 1 unit more of CDAI values.
cPrevious RA treatment includes treatment with biologics and/or MTX.
dOther csDMARDs included tacrolimus, salazosulfapyridine, bucillamine and mizoribine. No patients used leflunomide or targeted synthetic DMARDs.
eFor discontinuation patients, missing data were replaced by the last observed values.
CDAI: clinical disease activity index; CKD: chronic kidney disease; MCID: minimum clinically important difference; TCZ: tocilizumab; DMARDs: disease-modifying antirheumatic drugs; csDMARDs: conventional synthetic DMARDs; OR: odds ratio.