Multivariable analysis for predictors of major clinical response to first cycle rituximab
| No response/partial response n=59 | Major clinical response n=58 | Univariable OR (95% CI), p value (with multiple imputation) | Multivariable OR (95% CI), p value (with multiple imputation) | |
| Age, mean (SD) years | 43 (17) | 37 (14) | 0.97 (0.95 to 0.99), p=0.031 per year | 0.97 (0.94 to 1.00), p=0.045 |
| White, N (%) | 43 (73) | 37 (64) | 1.53 (0.70 to 3.34), p=0.292 | 0.92 (0.34 to 2.47), p=0.870 |
| Anti-dsDNA titres, mean (SD) IU/mL | 147 (230) | 142 (230) | 1.00 (0.99 to 1.00), p=0.879 per unit | 1.00 (0.99 to 1.00), p=0.632 |
| Anti-ENA positivity, N (%) | 40 (68) | 38 (66) | 0.91 (0.42 to 1.99), p=0.812 | 0.90 (0.37 to 2.22), p=0.821 |
| Low C3 and/or C4 titres, N (%) | 25 (42) | 24 (41) | 0.97 (0.46 to 2.04), p=0.937 | 1.14 (0.41 to 3.13), p=0.801 |
| ESR, mean (SD) mm/hour* | 40 (32) | 41 (36) | 1.00 (0.99 to 1.01), p=0.827 per unit | – |
| Concomitant S, N (%)† | 41 (69) | 35 (60) | 0.67 (0.31 to 1.43), p=0.301 | 0.43 (0.17 to 1.09), p=0.075 |
| Daily prednisolone dose, mean (SD) mg | 13 (11) | 16 (14) | 1.02 (0.99 to 1.05), p=0.207 per mg | 1.00 (0.97 to 1.04), p=0.713 |
| Total BILAG score, mean (IQR) | 21 (8) | 24 (13) | 1.03 (0.99 to 1.07), p=0.093 per point | 1.02 (0.97 to 1.07), p=0.371 |
| Total B-cell counts, mean (IQR)‡ | 101 (95) | 138 (150) | 1.00 (1.00 to 1.01), p=0.161 per unit | 1.00 (1.00 to 1.01), p=0.137 |
| B-cell depletion at 6 weeks postrituximab, N (%) | 29 (49) | 39 (68) | 2.10 (0.95 to 4.62), p=0.065 | 3.22 (1.24 to 8.33), p=0.016 |
*As high collinearity was observed between ESR and total B-cell counts, only the latter was included in the multivariable analysis.
†Concomitant immunosuppressant was defined as either using methotrexate, azathioprine, mycophenolate mofetil and/or other disease modifying anti-rheumatic drugs but excluded anti-malarials.
‡count × 109 cells/L) for each subset multiplied by 1000 prior to analysis.
BILAG, British Isles Lupus Assessment Group; C3/C4, complement 3 or 4; dsDNA, double-stranded DNA; ENA, extract nuclear antigen; ESR, erythrocyte sedimentation rate; IS, immunosuppressant.