Association of Systemic Lupus International Collaborating Clinics Frailty Index With Damage in Systemic Lupus Erythematosus Patients: Results From a Multiethnic, Multicenter US Cohort of Patients With Lupus

Objective: To evaluate the association between the Systemic Lupus International Collaborating Clinics frailty index (SLICC-FI) and damage accrual in systemic lupus erythematosus (SLE) patients. Methods: Patients from the multiethnic, multicenter LUpus in MInorities, NAture versus nurture (LUMINA) cohort were included. Damage was ascertained with the SLICC/American College of Rheumatology Damage Index (SDI) at last visit (range 0–51). The first visit in which the SLICC-FI score could be derived was considered as the baseline (range 0–1). Univariable and multivariable negative binomial regression models were performed to determine the association between the baseline SLICC-FI score (per 0.05 increase) and the change in the SDI score (difference between last and baseline SDI score), adjusted for sex, age at diagnosis, ethnicity, insurance, prednisone daily dose, and antimalarial and immunosuppressive drug use at baseline. Age and sex were included a priori in the multivariable model; the other variables were included if they reached P < 0.10 in the univariable models. Results: Of the 503 patients included, 454 (90.3%) were female, with a mean ± SD age of 37.1 ± 12.5 years at diagnosis. The mean ± SD baseline SLICC-FI score was 0.26 ± 0.06. The mean ± SD baseline SDI score was 0.6 ± 1.0, and the mean ± SD change in the SDI score was 1.9 ± 2.2. Higher SLICC-FI scores at baseline (per 0.05 increase) were associated with greater damage accrual in the multivariable model after adjustment for possible confounders (incidence rate ratio 1.20 [95% confidence interval 1.08–1.33], P = 0.0015). Conclusion: The SLICC-FI is associated with damage accrual in SLE patients from a multiethnic cohort, supporting the importance of this index in the evaluation of SLE patients, combining several aspects of their disease.