Remission, low disease activity, and relapse in patients with juvenile-, adult-, and late-onset systemic lupus erythematosus.

OBJECTIVE: To evaluate remission, low disease activity, and relapse in patients with systemic lupus erythematosus (SLE) according to age at disease onset. METHODS: We conducted a retrospective cohort study including patients classified with SLE according to the 2019 EULAR/ACR criteria. Patients were grouped by age at onset as juvenile-onset SLE (jSLE, <18 years), adult-onset SLE (aSLE, 18-49 years), and late-onset SLE (lSLE, ≥50 years). Patients with other autoimmune diseases were excluded, except antiphospholipid syndrome and Sjögren. Clinical data and outcomes were obtained from medical records. Remission was defined according to DORIS, low disease activity according to LLDAS, and relapse according to the SELENA-SLEDAI Flare Index. RESULTS: A total of 289 patients were included: 96 with jSLE, 96 with aSLE, and 97 with lSLE; 90.5% female. At diagnosis, jSLE patients had higher disease activity. Neuropsychiatric manifestations were more frequent in jSLE, while mucocutaneous involvement and nephritis predominated in aSLE. Remission and LLDAS were achieved more frequently in lSLE; concordantly, lSLE independently predicted remission and LLDAS (HR 2.8; 95% CI 1.9-4.0 and HR 2.4; 95% CI 1.7-3.4; p < 0.001). Relapses were more frequent in jSLE (87.5%) compared with aSLE (66.7%) and lSLE (24.7%; p < 0.001). Factors associated with relapse were jSLE (HR 2.1; 95% CI 1.5-2.9; p = 0.008) and constitutional manifestations at onset (HR 1.6; 95% CI 1.2-2.4; p = 0.048). Mortality was higher in lSLE, with infections as the main cause. CONCLUSION: Juvenile-onset SLE was associated with higher relapse rates, whereas late-onset SLE was independently associated with achieving remission and LLDAS.