1469: Remission, Low Level Disease Activity State (LLDAS) and Relapse in Patients With Early-Onset, Adult-Onset and Late-Onset Systemic Lupus Erythematosus

Background/Purpose: In systemic lupus erythematosus (SLE), differences have been observed between patients of different ages at onset. This study evaluates remission, low disease activity, and relapse in patients with SLE at different ages of onset.

Methods:

Design: Retrospective cohort study. We included patients classified with SLE according to the EULAR/ACR 2019 criteria, divided into three groups based on age at onset: early-onset (SLEe < 18 years), adult-onset (SLEa 18–49 years), and late-onset (SLEl ≥50 years). We excluded patients with other autoimmune diseases, except for antiphospholipid syndrome or Sjögren's syndrome. Information was collected through medical record review to obtain demographic data, disease characteristics (disease activity assessed by SLEDAI-2K, accrual damage by SLICC/ACR-DI, autoantibodies, and treatment); and outcomes (remission defined according to DORIS; low disease activity defined according to LLDAS and relapse defined by SELENA-SLEDAI Flare Index). The analysis period began at the date of diagnosis and included all rheumatology follow-up visits until relapse, death, or the last recorded rheumatology visit before December 2024. Demographic and disease characteristics were recorded at onset and during the follow-up period. Outcomes were assessed during follow-up.

Results: We included 289 SLE patients: 96 in the SLEe, 96 in the SLEa and 97 in the SLEl group. A total 90.5% were women. At disease onset, patients in the SLEa group exhibited higher disease activity compared to the other groups. Neuropsychiatric manifestations were more frequent in the SLEe group, whereas mucocutaneous manifestations and lupus nephritis were more prevalent in the SLEa group (Table 1). SLEa group compared to SLEe and SLEl had more prevalence of positive anti-cardiolipin IgG (46.2% vs. 34.2% vs 14%, p< 0.001), IgM (54.9% vs. 50.6% vs. 20.9%, p< 0.001) and positive lupus anticoagulant (27.3% vs. 16.9% vs. 7.1%, p=0.002). In contrast, SLEe group showed a higher prevalence of positive anti-β2 glycoprotein I compared to SLEa and SLEl (IgG: 29.9% vs. 22.7% vs. 1.2%, p< 0.001; IgM: 38.2% vs. 21.3% vs. 9.3%, p< 0.001). Differences in treatment among the groups are summarized in Table 1. Remission and LLDAS were more frequently achieved in the SLEl group compared to the SLEe and SLEa groups. Relapses were more frequent in SLEe group compared to the other groups (Table 1). Moreover, severe relapses were more common in SLEe patients than in those with SLEa or SLEl (63.5% vs. 42.7% vs. 14.4%, p< 0.001). Risk factors associated with relapse in studied patients included SLEe (HR 1.9, 95% CI, 1.4-2.8, p=0.008), constitutional manifestations at onset (HR 1.6, 95% CI, 1.2-2.2, p=0.048) and lupus nephritis during follow-up (HR 1.7, 95% CI, 1.2-2.4, p=0.024) (Table 2). Deaths occurred predominantly in SLEl group, with infections being the leading cause. Survival analysis of the outcomes is presented in Figure 1.

Conclusion: Patients with SLEe experienced more frequent relapses, while those with SLEl more often achieved remission and low disease activity. SLEe, constitutional manifestations at onset and lupus nephritis during follow-up were identified as risk factors for relapse.