Organ damage profiles and associated factors in juvenile versus adult-onset SLE: a matched analysis from the Japanese ANSWER-SLE cohort

Objectives To elucidate differences in organ damage in patients with systemic lupus erythematosus (SLE) between juvenile-onset (<18 years) and adult-onset (≥18 years) using the Systemic Lupus International Collaborating Clinics Damage Index (SDI). Methods Among patients in the multicenter registry, ANSWER-SLE (2019–2023), total-SDI and organ domains of SDI were compared between juvenile- and adult-onset patients after 1:2 matching based on sex and current age. Factors associated with total SDI and organ domains of SDI were analyzed by regression models in the total population. Results A total of 615 patients were included. Among them, 83 juvenile- and 166 adult-onset patients were matched. Juvenile-onset showed higher total-SDI (juvenile-onset vs. adult-onset, 2.17 vs. 1.16) and higher damage in the ocular, nervous system, renal, cardiovascular, and musculoskeletal domains than adult-onset. In the multivariable negative binomial regression analysis of the total cohort, younger age at onset (incidence rate ratio [IRR] 0.99, p=0.005) and older current age (IRR 1.03, p<0.001) were independently associated with higher total SDI scores. These associations persisted in the matched cohort (IRR 0.96 and IRR 1.03, respectively). In multivariable analyses of organ-specific damage adjusted for sex, current age, and age at onset, younger age at onset was associated with a higher SDI in the cataract, angina/coronary artery bypass, valvular disease, avascular necrosis, skin ulceration, and premature gonadal failure in the total cohort, and additionally with renal domain in the matched cohort. Conclusions Juvenile-onset SLE is associated with organ damage compared to adult-onset SLE, with prominent ocular, neurological, renal, cardiovascular, and musculoskeletal systems.