The 1000 Canadian faces of lupus: determinants of disease outcome in a large multiethnic cohort.
OBJECTIVE
To describe disease expression and damage accrual in systemic lupus erythematosus (SLE), and determine the influence of ethnicity and socioeconomic factors on damage accrual in a large multiethnic Canadian cohort.


METHODS
Adults with SLE were enrolled in a multicenter cohort. Data on sociodemographic factors, diagnostic criteria, disease activity, autoantibodies, treatment, and damage were collected using standardized tools, and results were compared across ethnic groups. We analyzed baseline data, testing for differences in sociodemographic and clinical factors, between the different ethnic groups, in univariate analyses; significant variables from univariate analyses were included in multivariate regression models examining for differences between ethnic groups, related to damage scores.


RESULTS
We studied 1416 patients, including 826 Caucasians, 249 Asians, 122 Afro-Caribbeans, and 73 Aboriginals. Although the overall number of American College of Rheumatology criteria in different ethnic groups was similar, there were differences in individual manifestations and autoantibody profiles. Asian and Afro-Caribbean patients had more frequent renal involvement and more exposure to immunosuppressives. Aboriginal patients had high frequencies of antiphospholipid antibodies and high rates of comorbidity, but disease manifestations similar to Caucasians. Asian patients had the youngest age at onset and the lowest damage scores. Aboriginals had the least education and lowest incomes. The final regression model (R2=0.27) for higher damage score included older age, longer disease duration, low income, prednisone treatment, higher disease activity, and cyclophosphamide treatment.


CONCLUSIONS
There are differences in lupus phenotypes between ethnic populations. Although ethnicity was not found to be a significant independent predictor of damage accrual, low income was.
Peschken
Christine A
CA
Department of Medicine, University of Manitoba Arthritis Center, RR149-800 Sherbrook Street, Winnipeg, Manitoba R3A 1M4, Canada. cpeschken@exchange.hsc.mb.ca
Katz
Steven J
SJ
Silverman
Earl
E
Pope
Janet E
JE
Fortin
Paul R
PR
Pineau
Christian
C
Smith
C Douglas
CD
Arbillaga
Hector O
HO
Gladman
Dafna D
DD
Urowitz
Murray
M
Zummer
Michel
M
Clarke
Ann
A
Bernatsky
Sasha
S
Hudson
Marie
M
D000328:Adult; D002170:Canada / Q000453:epidemiology; D005260:Female; D006304:Health Status; D006801:Humans; D007182:Income; D008180:Lupus Erythematosus, Systemic / Q000191:economics / Q000208:ethnology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care / Q000706:statistics & numerical data*; D011446:Prospective Studies; D044469:Racial Groups; D012720:Severity of Illness Index; D012923:Social Class; D011795:Surveys and Questionnaires