Objective: To examine the relationship between ethnicity and major organ involvement at and after diagnosis in community-based cohorts of Caucasian and Chinese systemic lupus erythematosus (SLE) patients resident in Rochester, Minnesota, and Singapore, respectively.
Methods: Clinical manifestations at and after diagnosis were compared in Caucasian and Chinese SLE patients. The association between ethnicity and disease manifestations at and after diagnosis was determined using logistic regression and Cox proportional hazards models, respectively, adjusting for the influence of demographic, socioeconomic, disease-related, and therapy-related factors.
Results: At diagnosis, Caucasian SLE patients were 3 times more likely than Chinese SLE patients to have serositis (odds ratio [OR] 3.11, 95% confidence interval [CI] 1.01-9.71), nearly 7 times more likely to have a hematologic disorder (OR 6.95, 95% CI 2.20-21.97), and far less likely to have a malar rash (OR 0.19, 95% CI 0.07-0.54) or positive antinuclear antibodies (OR 0.11, 95% CI 0.03-0.52). Ethnicity was not associated with the prevalence of proteinuria or central nervous system (CSN) and other major organ involvement at diagnosis. After diagnosis, there was a trend toward less development of proteinuria and other major organ involvement in Caucasians (relative risk [RR] 0.47, 95% CI 0.19-1.15, and RR 0.22, 95% CI 0.05-1.04, respectively).
Conclusion: Chinese SLE patients are far less likely to have serositis or a hematologic disorder at diagnosis and may be more likely to develop proteinuria or CNS or other major organ involvement over the course of the disease, compared with Caucasian SLE patients. This may contribute to the increased mortality seen in Chinese SLE patients.