Influence of age at disease onset in the outcome of paediatric systemic lupus erythematosus.

Objectives. The aim of this study was to investigate the influence of age at disease onset in the outcome of paediatric SLE (pSLE). Methods. Fifty-six patients with pSLE, divided into three groups (pre-pubertal, peripubertal and post-pubertal onset), were studied. The SDI (SLICC/ACR Damage Index for SLE), patients’ characteristics, disease manifestations and treatments were compared using Fisher’s exact test and Kruskal–Wallis test. Kaplan–Meier curves were constructed to compare the risk of damage occurrence. Results. The risk of damage (SDI 51) significantly decreased when age at disease onset increased (89% in pre-pubertal pSLE, 57% in peripubertal pSLE and 38% in post-pubertal pSLE). This excess of risk was found in all disease duration intervals studied (1–3, 3–5, 5–8, 8–10, >10 years) and at the end of follow-up. Kaplan–Meier curves indicated a higher and earlier risk of damage in younger patients. Young children showed higher frequency of autoimmune family history. The frequency of neuropsychiatric disorders and damages decreased with age at disease onset (P<0.05). Cumulative duration of high-dose prednisone (>0.5 mg/kg/day) and number of immunosuppressive drugs used that seem to contribute to damage significantly increased when age at disease onset decreased. Conclusions. The risk of damage is inversely correlated with age at disease onset in pSLE. The poorer outcome observed in younger children may be explained by a more severe disease expression, may be a higher infectious susceptibility, and a more aggressive therapy, particularly within the first 6 months of disease course.