Table 2.
Characteristics of the study participants matched on follow-up time and year of entry.
| Variables | Total (n = 360) | Infection cases (n = 120) | Controls (n = 240) |
|---|---|---|---|
| Age on diagnosis, years* | 36.3 ± 13.0 | 36.0 ± 14.5 | 36.5 ± 12.1 |
| Sex, female (%)* | 323 (89.7) | 106 (88.3) | 217 (90.4) |
| WBC, /µL | 6,708.1 ± 4,912.6 | 6,895.4 ± 5,038.8 | 6,614.5 ± 4,856.3 |
| N/L ratio | 7.6 ± 10.7 | 8.1 ± 12.7 | 7.4 ± 9.6 |
| Hemoglobin, /µL | 11.6 ± 1.9 | 11.1 ± 2.2 | 11.8 ± 1.7 |
| Platelet, × 103/µL | 206.7 ± 103.5 | 212.3 ± 108.8 | 204.0 ± 100.9 |
| ESR, mm/h | 35.5 ± 25.8 | 37.2 ± 30.9 | 34.6 ± 22.9 |
| Complement 3, mg/dL | 84.3 ± 39.9 | 78.2 ± 40.2 | 87.4 ± 39.5 |
| Complement 4, mg/dL | 18.9 ± 11.7 | 18.4 ± 13.4 | 19.2 ± 10.8 |
| Anti-dsDNA Ab, IU | 28.0 ± 34.9 | 31.7 ± 35.8 | 26.1 ± 34.4 |
| Oral ulcer, n (%) | 296 (82.2) | 102 (85.0) | 194 (80.8) |
| Arthritis, n (%) | 241 (66.9) | 76 (63.6) | 165 (68.8) |
| Nephritis, n (%) | 244 (67.8) | 49 (40.8) | 67 (27.9) |
| Serositis, n (%) | 73 (20.3) | 36 (30.0) | 37 (15.4) |
| Hematologic involvement, n (%) | 105 (29.2) | 50 (41.7) | 55 (22.9) |
| Hydroxychloroquine, n (%) | 314 (87.2) | 96 (80.0) | 218 (90.8) |
| Total dose of GCs, mga | 4,799.3 ± 6,653.5 | 5,227.3 ± 6,190.7 | 4,585.4 ± 6,875.7 |
| Mean dose of GCs, mg/da | 8.3 ± 14.6 | 10.4 ± 14.6 | 7.2 ± 14.5 |
| Dose of GCs | |||
| ≤7.5 mg/da | 247 (68.6) | 70 (58.3) | 177 (73.8) |
| >7.5 mg/da | 113 (31.4) | 50 (41.7) | 63 (26.3) |
| Immunosuppressive drugs | 172 (47.8) | 63 (52.5) | 109 (45.4) |
| Survival time, days* | 1,000 ± 1,040.2 | 1,000 ± 1,043.1 | 1,000 ± 1,040.9 |
| Cohort entry, year* | |||
| 1995–1997 | 8 (2.2) | 3 (2.5) | 5 (2.1) |
| 1998–2000 | 4 (1.1) | 1 (0.8) | 3 (1.3) |
| 2001–2003 | 52 (14.4) | 17 (14.2) | 35 (14.6) |
| 2004–2006 | 97 (26.9) | 34 (28.3) | 63 (26.3) |
| 2007–2009 | 80 (22.2) | 25 (20.8) | 55 (22.9) |
| 2010–2012 | 87 (24.2) | 30 (25.0) | 57 (23.8) |
| 2013–2015 | 32 (8.9) | 10 (8.3) | 22 (9.2) |
*Matching variable.
WBC: white blood cells, N/L ratio: Neutrophils/Lymphocyte ratio, ESR: erythrocyte sedimentation rate, dsDNA: double-strand deoxyribonucleic acid, Ab: antibody, GCs: glucocorticoids.
aPrednisolone-equivalent.