Table 1.
Patient characteristics.
| Baseline characteristics | Whole Cohort (n = 4627) | Stable (n = 3228, 69.8%) |
Flares within 0–3 months of 1st vaccine dose (n = 542, 11.7%) | Flares outside of 0–3 months after 1st vaccine dose (n = 312, 6.8%) | Improved (n = 545, 11.8%) |
|---|---|---|---|---|---|
| Age | 61 | 61 | 58 | 62 | 60 |
| (median years, IQR) | (48, 70) | (47, 70) | (46, 67) | (48, 70) | (51, 67) |
| Ethnicity | |||||
| Chinese | 3394 (73) | 2388 (74) | 395 (73) | 226 (72) | 385 (71) |
| Malay | 486 (11) | 322 (10) | 60 (11) | 31 (10) | 73 (13) |
| Indian | 473 (10) | 321 (10) | 61 (11) | 43 (14) | 48 (9) |
| Others | 274 (6) | 197 (6) | 26 (5) | 12 (4) | 39 (7) |
| Gender | |||||
| Female | 3293 (71) | 2313 (72) | 390 (72) | 205 (66) | 385 (71) |
| Vaccine type | |||||
| Pfizer/BioNTech | 4058 (88) | 2862 (89) | 459 (86) | 271 (87) | 466 (87) |
| Moderna | 523 (11) | 339 (11) | 76 (14) | 39 (13) | 69 (13) |
| Diagnosis | |||||
| Rheumatoid Arthritis | 1966 (42) | 1314 (41) | 264 (49) | 149 (49) | 239 (44) |
| Systemic Lupus Erythematosus | 641 (14) | 496 (15) | 51 (9) | 21 (7) | 73 (13) |
| Psoriatic Arthritis | 486 (11) | 302 (9) | 79 (15) | 41 (13) | 64 (12) |
| Spondyloarthropathies | 484 (10) | 325 (10) | 60 (11) | 46 (15) | 53 (10) |
| Sjogren's Syndrome | 261 (6) | 208 (6) | 22 (4) | 11 (4) | 20 (4) |
| Systemic sclerosis | 159 (3) | 128 (4) | 8 (1) | 7 (2) | 16 (3) |
| Treatment | |||||
| Methotrexate | 1684 (36) | 1088 (34) | 233 (43) | 124 (40) | 239 (44) |
| Sulfasalazine | 848 (18) | 553 (17) | 125 (23) | 73 (23) | 97 (18) |
| Hydroxychloroquine | 1389 (30) | 969 (30) | 154 (28) | 77 (25) | 189 (35) |
| Mycophenolate Mofetil | 296 (6) | 210 (7) | 32 (6) | 13 (4) | 41 (8) |
| Biological DMARDs | 383 (8) | 249 (8) | 57 (11) | 24 (8) | 53 (10) |
| JAK inhibitors | 46 (1) | 24 (1) | 6 (1) | 8 (3) | 8 (1) |
| Prednisolone dose (mg, median, IQR) | 0 (0,4) | 0 (0, 2.5) | 0 (0,5) | 0 (0,5) | 0 (0,5) |
| Baseline Physician Disease Activity | |||||
| Remission | 2188 (47) | 1761 (55) | 179 (33) | 115 (36) | 133 (24) |
| Low Disease Activity | 1897 (41) | 1235 (39) | 257 (47) | 157 (50) | 248 (46) |
| Moderate Disease Activity | 480 (10) | 213 (7) | 92 (17) | 37 (12) | 138 (25) |
| High Disease Activity | 62 (1) | 19 (1) | 14 (3) | 3 (0.96) | 26 (5) |
Data are shown in number (percentages) unless specified.