Childhood Systemic Lupus Erythematosus: Presentation, management and long-term outcomes in an Australian cohort

Abstract

Objectives: Systemic Lupus Erythematosus (SLE) is a serious autoimmune disease often resulting in major end-organ damage and increased mortality. Currently, no data exists focussing on the presentation, long-term management and progression of SLE in the Australian paediatric population. We conducted the first Australian longitudinal review of childhood SLE, focussing on response to treatment and outcomes.

Methods: Detailed clinical and laboratory data of 42 children diagnosed with SLE before 16 years from 1998 to 2018 resident in Western Australia was collected. Data was collected at diagnosis and key clinical review time points and compared using the Systemic Lupus Collaborating Clinics (SLICC) and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) criteria. End organ damage was assessed against Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (SDI). Incidence rates of disease complications and end organ damage were determined.

Results: Of the 42 children, 88% were female with average age at diagnosis of 12.5 years. Indigenous Australians were over represented with an incidence rate 18-fold higher than non-Indigenous, although most children were Caucasian, reflecting the demographics of the Australian population. Median duration of follow-up was 4.25 years. On final review, 28.6% had developed cumulative organ damage as described by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index (incidence rate: 0.08/PY (95% CI 0.04-0.14)), and one child died. Twenty-nine children had renal involvement (incidence rate: 0.38/PY (95% CI 0.26-0.56)). Of the 27 patients with biopsy proven lupus nephritis, 70% had Class III or IV disease. Average length of prednisolone use from diagnosis was 32.5 months. Hydroxychloroquine (n = 36) and mycophenolate mofetil (n =21) were the most widely used steroid sparing agents. 61.9% received rituximab and/or cyclophosphamide.

Conclusion: This is the first longitudinal retrospective review of Australian children with SLE, with a markedly higher incidence in Indigenous children. Although improving, rates of end organ complications remain high, similar to international cohort outcomes. Longitudinal multi-centre research is crucial to elucidate risk factors for poor outcomes, and identifying those warranting early more aggressive therapy.

Keywords: Systemic Lupus Erythematosus; morbidity; outcomes; paediatric; renal; treatment.