Background To compare disease manifestations and outcomes of juvenile-onset SLE (jSLE) and adult-onset SLE (aSLE) patients using a nested case control study of patients in a Singapore cohort.

Methods A prospective cohort of SLE patients was established at Tan Tock Seng Hospital from 1st January 2002 to 31st December 2017. Sociodemographic, clinical, laboratory and treatment data were collected according to a standardised protocol. jSLE patients (≤18 years old) were selected from this cohort and matched for gender and disease duration in a 1:1 ratio with aSLE patients. Data from the enrolment visit (V0) and last visit (VL) were analysed in this study.

Results There were 148 jSLE patients with sufficient information for analysis who were matched with 148 aSLE patients. Fever and lymphadenopathy (p<0.001) and hypocomplementemia (p=0.002 at V0) were significantly more common in jSLE, while cardiovascular manifestations were significantly more common in aSLE patients (p=0.008 at VL). Disease activity measured by the SLE Disease Activity Index (SLEDAI) was higher in the jSLE group at V0 (median SLEDAI 4 vs 2, p=0.05) and at VL (median SLEDAI 2.5 vs 0, p=0.007). A significantly higher proportion of jSLE patients received immunosuppressants (intravenous cyclophosphamide, mycophenolate mofetil, azathioprine and ciclosporin) (p=0.003 at V0, p<0.001 at VL) and intravenous methylprednisolone (p<0.001 at V0 and VL) compared to aSLE patients.

Conclusions A higher proportion of jSLE patients have fever, lymphadenopathy, hypocomplementemia; more active disease requiring greater use of immunosuppressants compared to aSLE patients. Early diagnosis and treatment of jSLE may prevent development of major organ involvement, in particular renal and neuropsychiatric disease.