Comparison of ethnicity, gender, age of onset and outcome in South Africans with systemic lupus erythematosus

Abstract

Ethnicity, gender and age of onset are reported to influence the expression and outcome of systemic lupus erythematosus. We studied a multi-ethnic cohort of 408 South Africans (91.2% females) comprising 237 (58.1%) Indians, 137 (33.6%) African Blacks, 17 (4.2%) Mixed ethnicity and 17 (4.2%) Whites. The most common manifestations were arthritis (80.6%), photosensitivity (67.2%), oral ulcers (50.0%), malar rash (49.0%) and renal (39.2%). The common laboratory findings were positive anti-nuclear factor (96.8%), haematological (74.8%) and anti-dsDNA antibodies (45.3%). Serositis ( p = 0.002), nephritis ( p = 0.039), leucopaenia ( p = 0.001), haemolytic anaemia ( p = 0.026), anti-dsDNA antibodies ( p = 0.028) and anti-Sm antibodies ( p = 0.050) were more common in African Blacks compared to Indians. Males had increased prevalence of discoid rash ( p = 0.006) and anti-Sm antibodies ( p = 0.016). Discoid rash ( p = 0.018), renal involvement ( p < 0.001), psychosis ( p = 0.028), seizures ( p = 0.020), anti-dsDNA antibodies ( p = 0.009), leucopaenia ( p = 0.006), haemolytic anaemia ( p = 0.017) and thrombocytopaenia ( p = 0.023) were more common with early-onset systemic lupus erythematosus. On multivariate analysis, the independent predictors of death were renal involvement, anti-dsDNA antibodies and seizures. There were 53 (13%) deaths and the five- and 10-year survival was 90.8% and 85.7% respectively, with no differences related to ethnicity or age of onset. In conclusion, we report on the spectrum and outcome of systemic lupus erythematosus in a large South African multi-ethnic cohort.