OBJECTIVE: The Systemic Lupus International Collaborating Clinics (SLICC) frailty index (FI) has been shown to predict mortality, but its association with other important outcomes is unknown. We examined the association of baseline SLICC-FI values with damage accrual in the SLICC inception cohort. METHODS: The baseline visit was defined as the first at which both organ damage (SLICC/ACR Damage Index [SDI]) and health-related quality of life (Short-Form 36 [SF-36]) were assessed. Baseline SLICC-FI scores were calculated. Damage accrual was measured by the increase in SDI between the baseline assessment and the last study visit. Multivariable negative binomial regression estimated the association between baseline SLICC-FI values and the rate of increase in the SDI during follow-up, adjusting for relevant demographic and clinical characteristics. RESULTS: The 1549 SLE patients eligible for this analysis were mostly female (88.7%) with mean (standard deviation, SD) age 35.7 (13.3) years and median (interquartile range) disease duration 1.2 (0.9-1.5) years at baseline. Mean (SD) baseline SLICC-FI was 0.17 (0.08) with a range of 0-0.51. Over a mean (SD) follow-up of 7.2 (3.7) years, 653 patients (42.2%) had an increase in SDI. Higher baseline SLICC-FI values (per 0.05 increment) were associated with higher rates of increase in the SDI during follow-up (Incidence Rate Ratio [IRR] 1.19; 95% CI 1.13-1.25), after adjusting for age, sex, ethnicity/region, education, baseline SLEDAI-2K, baseline SDI, and baseline use of corticosteroids, antimalarials, and immunosuppressives. CONCLUSION: The SLICC-FI predicts damage accrual in incident SLE, which further supports the SLICC-FI as a valid health measure in SLE
