Clinical characteristics and survival of 413 patients with systemic lupus erythematosus in southeastern areas of South Korea: A multicenter retrospective cohort study

AIMS: To investigate demographic, clinical, laboratory, and immunological characteristics of patients with systemic lupus erythematosus (SLE) in southeastern areas of South Korea, and to perform survival analysis. METHODS: We retrospectively evaluated 413 patients with SLE diagnosed in 3 tertiary rheumatology centers in South Korea from 1992 to 2016 by reviewing their medical charts. All patients fulfilled the 1997 revised American College of Rheumatology classification criteria for SLE. RESULTS: Most patients were women (92%), and the mean (+/-standard deviation) age at diagnosis was 30.9 (+/-12.9) years. The most common clinical manifestation was leukopenia (74.3%), followed by lymphopenia (73.6%), arthritis (59.1%), malar rash (48.4%), thrombocytopenia (46.5%), oral ulcer (35.1%), and biopsy-proven lupus nephritis (31.2%). Anti-nuclear, anti-double-stranded DNA, anti-Smith, and anti-Ro antibodies were positive in 97.8%, 70.1%, 38.4%, and 63% of patients, respectively. Twenty (4.8%) patients died during a median follow-up of 83 months, and the cumulative 5-year and 10-year survival rates were 96.9% and 95.5%, respectively. The major causes of death were infection (50%) and lupus flare-up (50%). Male (hazards ratio [HR] = 7.19, P = .001), pleuritis and/or pericarditis (HR = 3.28, P = .012), childhood-onset (HR = 3.57, P = .012), and late-onset (HR = 4.65, P = .011) were independent risk factors for death. Compared with SLE cohorts in other ethnicities or countries, our patients tended to have a higher frequency of anti-Ro antibodies and hematologic disorders. CONCLUSION: This study describes clinical features of SLE in South Korea and suggests a remarkable phenotypic heterogeneity of SLE.