INCIDENCE OF SYSTEMIC LUPUS-ERYTHEMATOSUS - RACE AND GENDER DIFFERENCES

Objective, To examine racial differences in the incidence of systemic lupus erythematosus (SLE). Methods, A population-based registry of SLE patients in Allegheny County, Pennsylvania, was used to identify inci dent cases of SLE diagnosed between January 1, 1985 and December 31, 1 990, from 3 sources, by medical record review (University of Pittsburg h Lupus Databank, rheumatologists, and hospitals), Capture-recapture m ethods using log-linear models were used to estimate the level of case -finding and to calculate 95% confidence intervals (CI), Incidence rat es were calculated per 100,000 population. Results, A total of 191 def inite and 78 probable incident cases of SLE were identified, and the o verall annual incidence rates were 2.4 (95% CI 2,1-2,8) and 1.0 (95% C I 0.8-1,3), respectively, The crude incidence rates of definite SLE we re 0.4 for white males, 3.5 for white females, 0.7 for African-America n males, and 9.2 for African-American females, The annual incidence ra tes of definite SLE remained fairly constant over the study interval, African-American females with definite SLE had a younger mean age at d iagnosis compared with white females (P < 0.05), Since the overall asc ertainment rate was high (85%; 95% CI 78-92%), the ascertainment-corre cted incidence rate for definite SLE, 2.8 (95% CI 2.6-3.2), was simila r to the crude rate. Conclusion, Our rates clearly confirm previous re ports of an excess incidence of SLE among females compared with males and among African-Americans compared with whites, We have used capture -recapture methods to improve the accuracy of SLE incidence rates, and we advocate their use to facilitate comparisons across studies.