POS1308 PREDICTORS OF DISEASE PROGRESSION IN A MONOCENTRIC COHORT OF 100 PATIENTS WITH CHILDHOOD-ONSET SYSTEMIC LUPUS ERYTHEMATOSUS
Authors: C. Chighizola, I. Pontikaki, S. Costi, G. Armentaro, M. Gattinara, T. Giani, R. Cimaz
Journal: Annals of the Rheumatic Diseases (2021)

Background: Childhood-onset systemic lupus erythematosus (cSLE) accounts for 10-20% of overall cases, usually presenting in early adolescence. SLE in children is characterized by a severe clinical course. Objectives: This study describes the evolution of clinical manifestations of cSLE, with the aims of i) identifying biomarkers predictive of disease progression and ii) assessing the effects of treatment on disease course. Methods: Laboratory and clinical data of cSLE patients followed in our Paediatric Rheumatology Unit were retrospectively collected at diagnosis and during follow-up. Continuous data were expressed as median (interquartile range [IQR]) and categorical data as percentages. The association between categorical variables was assessed by chi-squared test, the correlation between variables was tested by Pearson’s test. Univariate linear regression analyses were performed to investigate the relationship between the rate of new disease manifestations at follow-up and candidate predictors. Statistical analysis was performed using GraphPadPrism v6. P values &lt;0.05 were regarded statistically significant. Results: One-hundred patients (89% of female gender) with cSLE were included in this study, with a median age at disease onset of 13 years (10.5-15). Clinical details are presented in Table 1. Complement levels were reduced in 71 patients (C3 in 62 and C4 in 65). At a median follow-up of 118 months (57-239), the disease progressed in 93 patients, with a median of two new manifestations per patient (1-3). No correlation emerged between the number of new disease manifestations and both age at diagnosis and disease duration. Among serological biomarkers, a reduction in complement fractions at diagnosis emerged as the only predictor of new clinical manifestations due to cSLE (p=0.013 for low C3 and p=0.0004 for low C4). Among the several different pharmacological tools, hydroxychloroquine (HCQ, p=0.021, 95% confidence interval (CI) 0.0084-0.1007), azathioprine (AZA, p=0.0217, 95%CI 0.013-0.1703) and cyclophosphamide (CTX, p=0.0305, 95%CI 0.013-0.170) were identified as protective. At follow-up, patients most commonly developed new haematological and cutaneous involvements, which were diagnosed in 43 and 11 patients, respectively. A trend towards statistical significance emerged for low C4 levels to predict new haematological involvement at follow-up (p=0.064, chi-squared: 3.42). Differently, positivity for antibodies against dsDNA emerged as the only predictor of the onset of cutaneous manifestations during follow-up (p=0.022, chi-squared: 7.62). Low C3 levels approached statistical significance in the prediction of skin involvement (p=0.058, chi-squared 5.68). Conclusion: According to the data from our monocentric cohort of 100 patients, complement and anti-dsDNA antibodies are the most accurate tools to predict disease progression in cSLE. HCQ, AZA and CTX reduce the rate of disease progression. Table 1. Clinical manifestations, laboratory features and treatment details of recruited patients at diagnosis. Number of patients Skin manifestations 44 Haematological involvement 51 Lupus nephritis 16 Musculoskeletal involvement 72 Serositis 14 Neuropsychiatric involvement 6 Anti-nuclear antibodies 90 Anti-Ro antibodies 11 Anti-Sm antibodies 13 Anti-dsDNA antibodies 67 Anti-phospholipid antibodies 29 Hydroxychloroquine 89 Azathioprine 40 Cyclophosphosphamide 29 Micophenolate mofetil 13 Cyclosporine 15 Rituximab 1 Belimumab 2 Steroids 91 Disclosure of Interests: None declared