Objective: To examine childhood-onset disease as a predictor of mortality in a cohort of adult patients with systemic lupus erythematosus (SLE).
Methods: Data were derived from the University of California Lupus Outcomes Study, a longitudinal cohort of 957 adult subjects with SLE that includes 98 subjects with childhood-onset SLE. Baseline and followup data were obtained via telephone interviews conducted in 2002-2007. The number of deaths during 5 years of followup was determined and standardized mortality ratios (SMRs) for the cohort, and across age groups, were calculated. Kaplan-Meier life table analysis was used to compare mortality rates between childhood- (defined as SLE diagnosis at <18 years of age) and adult-onset SLE. Multivariate Cox proportional hazard models were used to determine predictors of mortality.
Results: During the median followup period of 48 months, 72 deaths (7.5% of subjects) occurred, including 9 deaths (12.5%) in subjects with childhood-onset SLE. The overall SMR was 2.5 (95% confidence interval [95% CI] 2.0-3.2). In Kaplan-Meier survival analysis, after adjusting for age, childhood-onset subjects were at increased risk for mortality throughout the followup period (P< 0.0001). In a multivariate model adjusting for age, disease duration, and other covariates, childhood-onset SLE was independently associated with an increased mortality risk (hazard ratio [HR] 3.1, 95% CI 1.3-7.3), as was low socioeconomic status measured by education (HR 1.9, 95% CI 1.1-3.2), and end stage renal disease (HR 2.1, 95% CI 1.1-4.0).
Conclusion: Childhood-onset SLE was a strong predictor of mortality in this cohort. Interventions are needed to prevent early mortality in this population.