Profile of 3 clusters.
| All Patients, n = 2239 | Patients With IA/CTD or Receiving Immunomodulatory Therapy, n = 1533 | |||||||
|---|---|---|---|---|---|---|---|---|
| C1, n = 295 | C2, n = 703 | C3, n = 1241 | P | IC1, n = 183 | IC2, n = 488 | IC3, n = 862 | P | |
| Age, yrs, median (IQR) | 55 (41–66) | 53 (40–64) | 55 (43–66) | 0.03 | 52 (40–65) | 51 (38–62) | 54 (41–64) | 0.008 |
| Male | 113 (38.3) | 223 (31.7) | 336 (27.1) | < 0.001 | 67 (36.6) | 135 (27.7) | 194 (22.5) | < 0.001 |
| Race | < 0.001 | < 0.001 | ||||||
| Chinese | 216 (73.2) | 493 (70.1) | 815 (65.7) | 135 (73.8) | 320 (65.6) | 547 (63.5) | ||
| Malay | 17 (5.8) | 67 (9.5) | 165 (13.3) | 8 (4.4) | 52 (10.7) | 120 (13.9) | ||
| Indian | 41 (13.9) | 78 (11.1) | 114 (9.2) | 26 (14.2) | 72 (14.8) | 89 (10.3) | ||
| Other | 21 (7.1) | 65 (9.2) | 147 (11.8) | 14 (7.7) | 44 (9.0) | 106 (12.3) | ||
| Unemployed | 109 (36.9) | 269 (38.3) | 584 (47.1) | < 0.001 | 59 (32.2) | 175 (35.9) | 393 (45.6) | < 0.001 |
| Comorbidities† | ||||||||
| Cancer | 10 (3.4) | 28 (4) | 42 (3.4) | 0.78 | 4 (2.2) | 11 (2.3) | 23 (2.7) | 0.86 |
| CVD | 20 (6.8) | 38 (5.4) | 80 (6.4) | 0.59 | 7 (3.8) | 18 (3.7) | 50 (5.8) | 0.17 |
| Diabetes mellitus | 14 (4.7) | 45 (6.4) | 75 (6) | 0.60 | 9 (4.9) | 33 (6.8) | 45 (5.2) | 0.45 |
| Hypertension | 14 (4.7) | 44 (6.3) | 74 (6) | 0.64 | 7 (3.8) | 25 (5.1) | 44 (5.1) | 0.75 |
| Antihypertensive drugs | 70 (23.7) | 180 (25.6) | 385 (31.1) | 0.03 | 41 (22.4) | 117 (23.9) | 277 (32.2) | 0.003 |
| CKD | 9 (3.1) | 16 (2.3) | 35 (2.8) | 0.71 | 5 (2.7) | 8 (1.6) | 17 (2.0) | 0.66 |
| Rheumatological diagnosis∗ | 0.25 | 0.01 | ||||||
| IA | 98 (33.2) | 243 (34.6) | 380 (30.6) | 94 (51.4) | 245 (50.2) | 382 (44.3) | ||
| CTD | 51 (17.3) | 154 (21.9) | 272 (21.9) | 49 (26.8) | 155 (31.8) | 273 (31.7) | ||
| Crystal arthritis | 24 (8.1) | 51 (7.3) | 90 (7.3) | – | – | – | ||
| Noninflammatory | 67 (22.7) | 126 (17.9) | 233 (18.8) | – | – | – | ||
| Medications | 0.27 | 0.19 | ||||||
| IS none | 98 (33.2) | 220 (31.3) | 381 (30.7) | 20 (10.9) | 62 (12.7) | 102 (11.8) | ||
| HCQ alone | 16 (5.4) | 69 (9.8) | 129 (10.4) | 14 (7.7) | 71 (14.5) | 129 (15.0) | ||
| IS including csDMARD | 138 (46.8) | 315 (44.8) | 579 (46.7) | 133 (72.7) | 320 (65.6) | 579 (67.2) | ||
| bDMARD or tsDMARD | 16 (5.4) | 34 (4.8) | 45 (3.6) | 16 (8.7) | 32 (6.6) | 47 (5.5) | ||
| Gout medications | 27 (9.2) | 65 (9.2) | 107 (8.6) | – | – | – | ||
Values are n (%) unless otherwise specified. Cluster groups: C1/C2/C3 used the whole cohort of patients who had responded to questionnaire. A subgroup analysis was carried out on patients with a diagnosis of connective tissue disease, inflammatory arthritis, and/or on immunosuppressive agents (IC1/IC2/IC3). Differences between clusters were tested using Kruskal-Wallis test for continuous measures and Pearson chi-square test for categorical measures.
↵∗Unknown = 450.
↵†CTD: Connective tissue disease, includes systemic lupus erythematosus, immune mediated inflammatory myositis, systemic sclerosis, systemic vasculitis, Sjögren syndrome, mixed CTD, undifferentiated CTD; IA: inflammatory arthritis, includes rheumatoid arthritis, psoriatic arthritis, axial and peripheral spondyloarthropathy, juvenile idiopathic arthritis, adult-onset Still disease, and undifferentiated IA; noninflammatory: includes primary antiphospholipid syndrome, osteoarthritis, osteoporosis, fibromyalgia, soft tissue rheumatism, and miscellaneous conditions. bDMARD: biologic disease-modifying antirheumatic drug; C1, C2, C3: cluster 1, 2, 3; CKD: chronic kidney disease; csDMARD: conventional synthetic disease-modifying antirheumatic drug; CVD: cardiovascular disease; HCQ: hydroxychloroquine; IS: immunosuppressant; tsDMARD: targeted synthetic disease-modifying antirheumatic drug.