[Systemic lupus erythematosus in the county of Fynen. An epidemiologic study]

The incidence and prevalence of systemic lupus erythematosus (SLE) has never been investigated in Denmark, whereas international studies have reached divergent results. In the study patients were ascertained from diagnosis-based registers of inpatients and outpatients, notifications from physicians, and an autoimmune register. Diagnoses were validated and patients classified according to the American College of Rheumatology criteria: definite SLE (D-SLE) > or = 4 and incomplete SLE (I-SLE) < 4 criteria. The point prevalence as of Jan. 1, 1995, was 21.7/100,000 (CI 95% 17.3-26.8) for D-SLE and 5.2/ 100,000 (CI 95% 3.2-8.0) for I-SLE. The mean annual incidence in 1990-94 was 2.5/100,000 (CI 95% 1.8-3.3). Figures for annual incidence and prevalence were in accordance with recent British reports but considerably lower than Swedish and Icelandic results. Although methodological issues should be considered, the results point to a different distribution of SLE in otherwise closely related nationalities.