Multivariate Poisson regression analysis: predictors of damage accrual over the follow-up (OR, 95% CI, p value)
| PDN ≤5 mg/day | PGA <0.5 | cSLEDAI=0 | PGA <0.5 plus PDN ≤5 mg/day | cSLEDAI=0 plus PGA <0.5 | cSLEDAI=0 plus PDN ≤5 mg/day | cSLEDAI=0 plus PGA <0.5 plus PDN ≤5 mg/day | |
| Five consecutive year remission | 0.498 (0.325 to 0.762) 0.0013 | 0.448 (0.278 to 0.721) 0.001 | 0.467 (0.311 to 0.702) <0.0001 | 0.431 (0.264 to 0.705) 0.001 | 0.470 (0.292 to 0.757) 0.002 | 0.499 (0.325 to 0.767) 0.002 | 0.442 (0.270 to 0.722) 0.001 |
| Four consecutive year remission | 0.534 (0.325 to 0.877) 0.013 | 0.322 (0.183 to 0.567) <0.0001 | 0.230 (0.138 to 0.385) <0.0001 | 0.400 (0.238 to 0.670) 0.001 | 0.338 (0.192 to 0.596) <0.0001 | 0.305 (0.186 to 0.500) <0.0001 | 0.389 (0.229 to 0.661) <0.0001 |
| Three consecutive year remission | 0.885 (0.567 to 1.382) 0.59 | 0.500 (0.328 to 0.764) 0.001 | 0.595 (0.393 to 0.900) 0.014 | 0.485 (0.313 to 0.754) 0.001 | 0.527 (0.345 to 0.805) 0.003 | 0.590 (0.387 to 0.899) 0.0014 | 0.490 (0.315 to 0.760) 0.0019 |
| Two consecutive year remission | 0.878 (0.562 to 1.370) 0.56 | 0.631 (0.444 to 0.896) 0.010 | 0.531 (0.371 to 0.759) 0.001 | 0.554 (0.381 to 0.805) 0.002 | 0.574 (0.400 to 0.826) 0.003 | 0.543 (0.376 to 0.785) 0.001 | 0.532 (0.363 to 0.781) 0.001 |
| 1-year remission | 1.022 (0.642 to 1.627) 0.92 | 0.868 (0.632 to 1.194) 0.386 | 0.915 (0.652 to 1.284) 0.606 | 0.845 (0.610 to 1.171) 0.313 | 0.913 (0.668 to 1.248) 0.566 | 1.072 (0.770 to 1.494) 0.679 | 0.877 (0.636 to 1.208) 0.422 |
| Age at baseline | 1.031 (1.019 to 1.042) <0.001 | 1.029 (1.017 to 1.040) <0.001 | 1.032 (1.021 to 1.044) <0.001 | 1.029 (1.017 to 1.041) <0.001 | 1.029 (1.017 to 1.041) <0.0001 | 1.033 (1.033 to 1.045) <0.001 | 1.029 (1.018 to 1.041) <0.001 |
| Previous GC pulses | ns | 1.441 (1.100 to 1.888) 0.008 | 1.369 (1.044 to 1.795) 0.023 | 1.452 (1.109 to 1.901) 0.007 | 1.447 (1.105 to 1.895) 0.007 | 1.457 (1.112 to 1.908) <0.006 | 1.463 (1.117 to 1.915) 0.006 |
| Previous vasculitis | ns | 1.660 (1.175 to 2.346) 0.004 | 1.689 (1.195 to 2.387) 0.003 | 1.656 (1.171 to 2.341) 0.004 | 1.677 (1.187 to 2.370) 0.003 | 1.666 (1.181 to 2.350) <0.004 | 1.666 (1.179 to 2.355) 0.004 |
| Cumulative GC dose at baseline | 1.008 (1.001 to 1.016) 0.025 | ns | 1.008 (1.000 to 1.015) 0.036 | 1.007 (1.000 to 1.014) 0.043 | ns | 1.008 (1.001 to 1.015) 0.023 | 1.007 (1.000 to 1.042) 0.046 |
| aPL syndrome | 1.377 (1.008 to 1.882) 0.044 | ns | 1.383 (1.016 to 1.882) 0.039 | ns | ns | ns | ns |
| AIC | 1033.68 | 1031.74 | 1014.99 | 1032.56 | 1032.52 | 1020.78 | 1031.48 |
| BIC | 1136.52 | 1107.74 | 1090.01 | 1108.56 | 1108.52 | 1096.79 | 1107.49 |
| P value | <0.0001 | <0.0001 | <0.0001 | <0.0001 | <0.0001 | <0.0001 | <0.0001 |
Variables with a p<0.2 at the univariate analysis were entered in the multivariate analysis: duration of remission (categorical variable with six levels) and the following characteristics: sex, age, disease duration, baseline SDI, cumulative GC dose at baseline, previous GC pulses, previous cyclophosphamide treatment, previous neurological and renal involvement, previous vasculitis, antiphospholipid syndrome. cSLEDAI, clinical SLE Disease Activity Index 2000. Significant variables are given in grey cells. The table reports only variables with at least one p<0.05 at the multivariate analysis for at least one remission definition.
Goodness-of-fit of different models according to the seven definitions of remission are also reported.
AIC, Akaike Information Criterion; aPL, antiphospholipid antibody; BIC, Bayesian Information Criterion; GC, glucocorticoid; ns, not significant; PDN, prednisone-equivalent; PGA, physician global assessment; SDI, Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index.