AB0500 FLARES AND DISEASE-RELATED DAMAGE IN LATE-ONSET SYSTEMIC LUPUS ERYTHEMATOSUS
Authors: Jiacai Cho, Preeti Dhanasekaran, Lay Kheng Teoh, Liang Shen, Aisha Lateef
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Late-onset systemic lupus erythematosus (SLE) and its disease-related outcomes have not been previously examined in a multi-ethnic Southeast Asian cohort. <h3>Objectives:</h3> To compare the following outcomes between patients with adult-onset versus late-onset SLE a) Disease manifestations at baseline b) Frequency of flares, defined by the SELENA Flare Index (SFI) c) Baseline damage and damage accrual, defined by the SLICC/ACR Damage Index (SDI) <h3>Methods:</h3> We prospectively enrolled patients ≥ 21 years old with SLE who fulfilled either the 1997 ACR Criteria or the 2012 SLICC Classification Criteria and followed each patient at three-monthly intervals for up to 5 years. Baseline demographics, disease manifestations, antibody profile were captured. At each visit, disease activity was measured using SLEDAI-2k. SDI was measured annually. We defined late-onset SLE as onset of symptoms at ≥50 years of age and adult-onset SLE as onset of symptoms at ≥18 but &lt;50 years of age. We excluded patients with symptom onset before 18 years of age. We compared the baseline demographic, disease manifestations and antibody profile between the adult-onset and late-onset patients. We analysed continuous variables using the Mann-Whitney U test and categorical variables using the Chi-square test. Bonferroni correction for multiple comparisons was done. We then compared the time to first flare between the two groups using the logrank test. Baseline SDI scores and the proportion of patients who have increased SDI ≥1 over follow-up were compared using Chi-square tests. <h3>Results:</h3> Of the 214 patients recruited, 154 (72.0%) were Chinese and 197 (92.1%) were females. One-hundred and ninety-three (90.2%) were on anti-malarial therapy and 141 (66.2%) were on immunosuppressive agents other than corticosteroids. The median (SD) age of recruitment of the 184 adult-onset SLE patients was 30.0 (22.5-37.5) years while the median (SD) age of recruitment of the 30 late-onset SLE patients was 53.0 (50.0-56.5) years. The median (IQR) disease duration was 8.12 (2.75-13.5) years among the adult-onset patients and 5.73 (1.52-9.95) years among the late-onset patients. Arthritis was the only disease manifestation that was different between the two groups (66.8% in the adult-onset group versus 36.7% in the late-onset group, <i>p</i>=0.002). There were no significant differences in the demographics and antibody profile between the two groups. The median (IQR) baseline Systemic Lupus Erythematosus Disease Activity Index-2k (SLEDAI-2k) was 3 (1-5) and 2 (0-4) in the adult-onset and late-onset patients respectively (<i>p</i>=0.086). The median (IQR) number of all flares per year was 0.41 (0-0.91) among adult-onset patients and 0.25 (0-0.55) among late-onset patients (<i>p</i>=0.206). There was no significant difference in the time to first flare or time to first severe flare between the two groups [mean (SD) time to any flare 2.51 (0.15) years in the adult-onset group versus 2.77 (0.34) years in the late-onset group, <i>p</i>=0.521; mean (SD) time to severe flare 3.90 (0.14) years among adult-onset patients versus 4.27 (0.28) years among late-onset patients, <i>p</i>=0.336]. The median (IQR) SDI at baseline was 0 (0-1) in adult-onset patients and 1 (1-2) in late-onset patients (<i>p</i>=0.049). There was no significant difference in the proportion of patients who accrued further damage during follow-up (7.9% of adult-onset patients versus 14.3% of late-onset patients,<i> p</i>=0.268). <h3>Conclusion:</h3> Although Southeast Asian patients with late-onset SLE have higher disease-related damage at recruitment, baseline disease activity and frequency of flares were similar to patients with SLE of adult-onset. <h3>References</h3> <h3>Disclosure of Interests:</h3> None declared