Differences in Clinical Features and Mortality between Childhood-onset and Adult-onset Systemic Lupus Erythematosus: A Prospective Single-center Study

Objective. To compare clinical features and mortality between childhood-onset systemic lupus erythematosus (cSLE) and adult-onset SLE (aSLE) in a prospective single-center cohort. Methods. A total of 1112 patients with SLE (133 cSLE and 979 aSLE) were enrolled and followed from 1998 to 2012. The 2 groups were compared regarding American College of Rheumatology (ACR) classification criteria for SLE, autoantibodies, disease activity measured by the Adjusted Mean SLE Disease Activity Index (AMS), damage measured by the Systemic Lupus International Collaborating Clinics/ACR Damage Index (SDI), and medication. The standardized mortality ratio (SMR) was calculated. Predictors of mortality in SLE were evaluated using Cox proportional hazard models. Results. After a mean followup of 7.6 years, patients with cSLE had a higher number of cumulative ACR criteria and a higher AMS (p < 0.001 each), but there was no difference in SDI (p = 0.797). Immunosuppressants were used more frequently by patients with cSLE (p < 0.001). The SMR of cSLE was 18.8 (95% CI 8.6-35.6), significantly higher than that of aSLE (2.9, 95% CI 2.1-3.9). We found cSLE to be an independent predictor of mortality (HR 3.6, p = 0.008). Moreover, presence of hemolytic anemia (7.2, p = 0.034) and antiphospholipid antibody (aPL; 3.8, p = 0.041) increased the magnitude of risk of early mortality more in the patients with cSLE than in those with aSLE. Conclusion. The clinical course of cSLE as measured by number of clinical manifestations and disease activity is worse than that of aSLE. Also, cSLE patients with hemolytic anemia and aPL are at greater risk of death than patients with aSLE who have those features.