AB1004 JUVENILE DERMATOMYOSITIS (JDM) IN SOUTHEAST ASIA: A 20-YEAR SINGAPORE EXPERIENCE
Authors: K. L. Teh, L. Das, Y. X. Book, T. Arkachaisri
Journal: Annals of the Rheumatic Diseases (2020)

Background: Juvenile dermatomyositis (JDM) is a multisystem inflammatory disease of childhood with variable demographics, clinical features and outcomes. No studies have described the characteristics of JDM patients from Southeast Asia population. Objectives: To describe the clinical characteristics and outcomes of JDM patients in Singapore over a 20-year period. Methods: Patients diagnosed with JDM from 1999 to 2019 at KK Women’s and Children’s Hospital, Singapore, were recruited. Nonparametric descriptive statistics were used to described data. Kaplan-Meier analyses were used to estimate the probability of remission. Multivariate logistic and Cox regression analyses were used to determine predictors as appropriate. The significant level was set at &lt; 0.05. Results: 32 JDM were identified. Clinical characteristics and treatment used are shown in Table 1. All (n=32) Monophasic (n=17) Polyphasic (n=14) Male 14 (43.8) 7 (41.2) 7 (50.0) Age at onset (yrs)* 6.4 (4.5 – 9.8) 5.4 (4.1 – 8.5) 7.4 (5.6 – 12.3) Lag period (mo)* 3.5 (1.0 – 12.5) 2.0 (1.0 – 16.8) 6.8 (1.2 – 15.8) Heliotrope 16 (50) 9 (52.9) 7 (50) Gottron papule 23 (71.9) 12 (70.6) 11 (78.6) Malar rash 19 (61.3) 9 (52.9) 10 (71.4) Vasculitic rash 19 (61.3) 8 (47.1) 11 (78.6) Arthritis 10 (31.3) 3 (17.6) 7 (50) Nailfold changes 28 (87.5) 15 (88.2) 13 (92.9) Calcinosis 9 (28.1) 4 (23.5) 5 (35.7) Positive ANA 17 (53.1) 10 (58.8) 7 (50) Positive Myositis antibodies 4 (12.5) 2 (11.8) 2 (14.3) Laboratory at diagnosis, U/L* CK 324 (134 – 2229) 746 (139 – 2965) 351 (155 – 2622) LDH 650 (450 – 943) 650 (398 – 1015) 714 (512 – 944) ALT 28 (16 – 106) 35 (18 – 109) 38 (15 – 104) AST 50 (30 -108) 50 (31 – 113) 85 (36 – 215) Aldolase 13.7 (8.1 – 28.0) 14.2 (8.4 – 26.6) 16.3 (8.6 – 38.5) CMAS score at diagnosis 29 (21 – 43) 28 (21 – 35) 35 (11 – 43) *median (IQR), otherwise - n (%) Pulse methylprednisolone (pMP) was used in 53.1% of patients after diagnosis. Median time to inactive disease (ID) was 5.3 months (IQR 2.8 – 12.8). Male, older age and patients on pMP (p = 0.003-0.044) achieved ID sooner. Older patients also developed disease flare sooner after achieving ID (p =0.024). No clinical features nor lab investigations predicted JDM disease course. Malay patients was associated with higher risk of calcinosis (p = 0.017). Compared to adult dermatomyositis patients in Singapore 1 , our cohort had more cutaneous manifestations including malar rash, vasculitic rash and nailfold changes. Table 2 shows the time for each muscle enzymes to normalise. CK 1.49 (0.69 – 3.53) LDH 4.53 (2.35 – 25.04) ALT 1.71 (0.90 – 4.13) AST 0.97 (0.53 – 3.12) Aldolase 3.12 (2.35 – 8.30) median in months (IQR) Conclusion: Our cohort of JDM patients had more calcinosis compared to other Asian population 2 . Malay population is at higher risk of this complication. It is crucial to achieve ID state in the shortest time possible to avoid significant morbidity. Our study suggests that early treatment with pMP is associated with shorter time to ID. There is no predictor identified for disease course, similar to previous studies 3 . References: [1]Liu, Wen Chun, et al. “An 11-year review of dermatomyositis in Asian patients.” Annals Academy of Medicine Singapore 39.11 (2010): 843. [2]Sun, Chi, et al. “Juvenile dermatomyositis: a 20-year retrospective analysis of treatment and clinical outcomes.” Pediatrics &amp; Neonatology 56.1 (2015): 31-39. [3]Stringer, Elizabeth, Davinder Singh Grewal, and Brian M. Feldman. “Predicting the course of juvenile dermatomyositis: significance of early clinical and laboratory features.” Arthritis &amp; Rheumatism: Official Journal of the American College of Rheumatology 58.11 (2008): 3585-3592. Disclosure of Interests: None declared