Onset age affects mortality and renal outcome of female systemic lupus erythematosus patients: a nationwide population-based study in Taiwan

Abstract

The objective of this study was to investigate the impact of disease onset age on mortality and renal survival in female SLE patients. This nationwide, population-based, retrospective cohort study used data from the National Health Insurance Research Database of Taiwan. Female patients newly diagnosed with SLE from 2001 to 2004 were identified as the study cohort. A non-SLE group was matched for age, sex and initial diagnosis date (index date) as the comparison cohort. Co-morbidities, mortality rates and end-stage renal disease (ESRD) incidences were compared among SLE patients of different onset age. Hazard ratios with a 95% CI were determined by the Cox proportional hazard model to quantify the mortality rates and ESRD incidences. Juvenile-onset, adult-onset and late-onset SLE patients were categorized according to disease onset age: <18, 18-50 and >50 years old. In total, 513 juvenile-onset, 3076 adult-onset and 764 late-onset SLE patients were identified. Compared with non-SLE controls, the hazard ratios of mortality were 6.49 (95% CI 3.73, 11.32, P < 0.001) for juvenile-onset, 1.75 (95% CI 1.47, 2.08, P < 0.001) for adult-onset and 3.44 (95% CI 2.76, 4.28, P < 0.001) for late-onset SLE patients. The hazard ratios of incident ESRD were 20.28 (95% CI 12.79, 32.15, P < 0.001) for adult-onset lupus patients and 1.99 (95% CI 1.36, 2.93, P < 0.001) for late-onset patients. Female patients with late-onset SLE carried a higher risk of mortality than those with adult-onset disease in the presence of co-morbidities. Juvenile-onset SLE patients were at greatest risk of mortality, which is probably due to disease severity.