Ethnic variation in disease patterns and health outcomes in systemic lupus erythematosus

In a single-center multiethnic lupus cohort, to investigate the influence of ethnicity on the prevalence of cumulative renal and central nervous system (CNS) lupus disease and damage, overall end-organ damage, and mortality.

Clinical features, end-organ damage, and mortality were compared by ethnic origin among patients at a lupus clinic followed prospectively in a longitudinal design over a 32-year period. Statistical analysis to compare demographic features, cumulative disease manifestations, and damage included chi-square test as well as linear, logistic, and Poisson regressions adjusting for disease duration, age at diagnosis, and presence of dialysis and hypertension. Kaplan-Meier and proportional hazard analyses were performed to compare survival.

There were a total of 1017 patients: 853 Caucasian, 88 African-Canadian, and 76 Chinese-Canadian. Age at diagnosis was younger and disease duration was shorter for Chinese-Canadians compared to Caucasians, but similar between African-Canadians and Caucasians. There was no significant difference in CNS disease, comparing Caucasians to Chinese-Canadians. However, CNS disease was greater in African-Canadians than Chinese-Canadians. There was no significant difference between ethnic groups in CNS damage. Renal disease was more common in African-Canadians than Caucasians, with no significant difference between Caucasian and Chinese-Canadian patients. Renal damage was more common in African-Canadians and Chinese-Canadians than Caucasians. There was no significant difference in mortality among the 3 ethnic groups.

In this single referral center cohort study, there was no significant difference in CNS damage or mortality among the 3 ethnic groups. African-Canadians had a higher prevalence of renal disease and damage. Further investigation into other determinants such as genetic predisposition, treatment, and cultural perceptions is needed.