Table 4.
Negative binomial regression models for the association of baseline SLICC-FI and SDI scores with the change in SDI scores during follow-up among SLE patients, excluding damage-related health deficits from the SLICC-FI.
| Univariable model (n=1549) |
Multivariable model a (n = 1539) |
|
|---|---|---|
| Incidence Rate Ratio (95% CI) |
Incidence Rate Ratio (95% CI) |
|
| Model 1: SLICC-FI | ||
| SLICC-FI b (per 0.05) | 1.17 (1.12 – 1.21) | 1.13 (1.09 – 1.17) |
| Model 2: SDI | ||
| SDI (per 1.0) | 1.31 (1.20 – 1.43) | 1.17 (1.07 – 1.28) |
| Model 3: SLICC-FI & SDI | ||
| SLICC-FI b (per 0.05) | 1.15 (1.11 – 1.20) | 1.12 (1.08 – 1.16) |
| SDI (per 1.0) | 1.26 (1.15 – 1.37) | 1.15 (1.05 – 1.25) |
| Overall model comparisons | LR test statistic (p value) |
LR test statistic (p value) |
| Model 1 vs. Model 3 | 26.46 (p<0.0001) | 10.74 (p=0.001) |
| Model 2 vs. Model 3 | 61.25 (p<0.0001) | 35.72 (p<0.0001) |
| Akaike Information Criteria (AIC) | ||
| Model 1: SLICC-FI | 3752.61 | 3577.12 |
| Model 2: SDI | 3787.41 | 3602.09 |
| Model 3: SLICC-FI & SDI | 3728.16 | 3568.37 |
a
Models adjusted for the following baseline characteristics: age, sex, steroid use, antimalarial use, immunosuppressive use, ethnicity/location, post-secondary education, and SLEDAI-2K.
b
Baseline SLICC-FI calculated using the 33 health deficits not related to organ damage.
Notes: SLICC = Systemic Lupus International Collaborating Clinics; FI = Frailty Index; SDI = SLICC / ACR Damage Index; LR = Likelihood Ratio