Sm antibodies increase risk of death in systemic lupus erythematosus

The importance of ethnicity, socioeconomic status (SES), and autoantibodies as prognostic indicators in lupus were evaluated in a Canadian cohort. A retrospective review of 330 lupus patients identified demographic features including age and self reported ethnicity, SES, lupus features, antibodies to extractable nuclear antigens (ENAs), organ damage (SDI score), and mortality. ENA (Sm, RNP, Ro, La) associations with lupus features, predictors of final visit SDI score and the contributions of ethnicity, autoantibodies and SES on overall mortality were determined. Three ethnic groups [Caucasians (C), Asian-Orientals (AO), Native American First Nations (FN)] differed in disease severity and SES. FN and AO patients had similarly severe lupus, developing lupus at an earlier age, with more renal and neurological involvement, greater SDI scores at last visit, and more frequently had Sm or RNP antibodies than C. FN had the highest mortality and lowest SES. Sm and RNP antibodies were associated with renal and neurologic involvement. RNP, education and duration of follow-up predicted SDI score. Sm increased risk of death. In conclusion, RNP and lower SES are associated with lupus related organ damage and the presence of Sm is a predictor of mortality in lupus, independent of ethnicity, renal involvement or socioeconomic status.