Development of additional autoimmune diseases in a multiethnic cohort of patients with systemic lupus erythematosus with reference to damage and mortality.

OBJECTIVES: To determine the prevalence of other autoimmune diseases (AID) in black, Caucasian and South Asian patients with systemic lupus erythematosus (SLE) compared with the prevalence of these AID in the UK population, and to assess the impact of these additional AID on damage scores and mortality. METHODS: The prevalence and chronology of development of additional AID in SLE patients was determined by case note review. Comparisons were made with prevalence data for AID in the general UK population. The impact of additional AID on mortality and damage scores at up to 10 years was determined in the index cases (patients who developed another AID either in the same year or within 5 years of onset of SLE) compared with controls matched for sex, age, ethnicity and year of onset of SLE. RESULTS: There was no significant difference in the total number of AID that developed in patients from each ethnic group but differences in the frequency of some AID were noted. Mortality and damage scores were worse at 5 years in the study cases than the controls, particularly in the peripheral vascular category. CONCLUSION: Patients with SLE might develop other AID that could complicate management of SLE by having an adverse impact on damage scores and mortality.