Survival analysis of late-onset systemic lupus erythematosus: a cohort study in China

The aim of this study is to explore the survival rate and risk factors of mortality in patients with late-onset systemic lupus erythematosus (SLE) in a large cohort. Clinical presentations, disease activity, organ damage scores, autoantibody profile, and mortality data were obtained retrospectively from late-onset SLE patients (onset age ≥50 years) diagnosed between 1995 and 2009. The risk factors of organ damage were evaluated by the chi-square test and logistic regression. The cumulative rate of survival was calculated by Kaplan–Meier method, and factors predictive of mortality were studied by Cox proportion hazard regression model. A total of 158 patients (132 female and 26 male) were studied. The average onset age was 58.66 ± 6.38 years and mean disease duration was 63.85 ± 48.17 months. One hundred and four patients had organ damage at the time of data analysis. Hematological system and kidney involvement were most common. Central nervous system involvement was relatively rare. In univariate logistic analysis, associations were found between SLE disease activity index (SLEDAI) at diagnosis (OR = 1.133, P = 0.001); renal involvement (OR = 2.441, P = 0.009) and edema (OR = 2.812, P = 0.003) were associated with organ damage. And SLEDAI at diagnosis (OR = 1.103, P = 0.034) was independent factor for organ damage in multivariate logistic regression. During the follow-up, 64 patients (51 female and 13 male) died. Five-, 10-, and 15-year survival rates were 80.4, 56.5, and 31.7 %, respectively. Median survival time was 123 months. The analysis of Cox proportion hazard regression model showed that age at disease onset (OR = 1.069, P = 0.002), compliance of medical care (OR = 3.282, P = 0.001), and SLEDAI at diagnosis (OR = 1.091, P = 0.003) were independent risk factors of mortality. Late-onset SLE has a poor long-term prognosis. Infection is the major cause of death in patients with late-onset lupus. Disease activity, medical care, and onset age are strongly related to death of late-onset SLE.