BACKGROUND/PURPOSE: The long-term impact of childhood-onset systemic lupus erythematosus on Health-related Quality of Life (HRQoL) in adult SLE patients in comparison to those with adult-onset SLE is unknown. We aim to examine and compare HRQoL trajectories in adults with adolescent- and adult-onset SLE.METHODS: Patients enrolled in the LUMINA cohort were included. Adolescent-onset SLE were those diagnosed <24years of age, and adult-onset SLE otherwise. Sociodemographic, clinical, medications, behavioral/psychological and functioning data were obtained. Longitudinal trajectories of the physical component (PCS) and the mental component (MCS) SF-36 summary scores were compared between the groups using a linear mixedmodel accounting for time-dependent and independent covariates.RESULTS: 470 SLE patients were included (95 adolescent-onset SLE and 375 adult-onset SLE). The mean age at diagnosis was 19.7years (SD: 2.8) in the adolescent group and 39.3years (SD: 11.0) in the adult group. Baseline PCS was higher (better physical functioning) in adolescent- when compared to adult-onset SLE (38.9 vs 34.3 respectively, p<0.001); however, the baseline MCS scores was comparable between the groups (41.4 vs 40.5 respectively, p=0.53). The HRQoL improved equally in both groups with no statistically significant difference within and between the groups (last PCS and MCS mean scores: 43.9 and 45.3 in adolescent-onset SLE; 38.1 and 43 in adult-onset SLE respectively).CONCLUSIONS: Adults with adolescent-onset SLE exhibited better physical functioning when compared with the adult SLE group despite more severe disease; noteworthy, HRQoL was below the general US population despite clinically meaningful improvement in HRQoL over time in both groups.