Occurrence of systemic lupus erythematosus in a Danish community: an 8-year prospective study

Scand J Rheumatol. Mar-Apr 2009;38(2):128-32. doi: 10.1080/03009740802419073.


Objectives: To determine the prevalence and annual incidence of definite systemic lupus erythematosus (D-SLE) and incomplete SLE (I-SLE) in a community-based lupus cohort of predominantly Nordic ancestry in an 8-year prospective study from 1995 to 2003, and also to calculate the annual transition rate of I-SLE to D-SLE.

Methods: In 1995 all SLE patients in the county of Funen were retrieved from four separate and independent sources. Incident cases were subsequently identified by surveillance of these sources.

Results: During the 8-year study period the median annual incidence of D-SLE (1.04 per 100 000) and I-SLE (0.36 per 100 000) remained almost constant. The point prevalence (PP) of D-SLE increased from 21.9 to 28.3 per 100 000, and from 6.19 to 7.53 per 100 000 for I-SLE. During follow-up, seven I-SLE patients transformed into D-SLE at a progression rate of 3.64 per 100 person-years at risk [95% confidence interval (CI) 1.44-7.55].

Conclusions: Denmark is a low-incidence lupus area but lupus prevalence is increasing slowly. I-SLE is a disease variant that may eventually convert into D-SLE.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Age Distribution
  • Aged
  • Aged, 80 and over
  • Child
  • Denmark / epidemiology
  • Disease Progression
  • Female
  • Humans
  • Incidence
  • Lupus Erythematosus, Systemic / diagnosis
  • Lupus Erythematosus, Systemic / epidemiology*
  • Lupus Erythematosus, Systemic / physiopathology
  • Male
  • Middle Aged
  • Prevalence
  • Prospective Studies
  • Registries
  • Young Adult