title: The incidence and prevalence of systemic lupus erythematosus in the UK, 1999-2012.
abstract: OBJECTIVE
  To estimate the incidence and prevalence of systemic lupus erythematosus (SLE) in the UK over the period 1999-2012.
  
  
  METHODS
  A retrospective cohort study using the Clinical Practice Research Datalink (CPRD). The incidence was calculated per 100 000 person-years and the prevalence was calculated per 100 000 people for the period 1999-2012 and stratified by year, age group, gender, region and ethnicity. Three definitions of SLE were explored: (1) systemic lupus, (2) a fully comprehensive definition of lupus including cutaneous only lupus and (3) requiring supporting evidence of SLE in the medical record.
  
  
  RESULTS
  Using our primary definition of SLE, the incidence during the study period was 4.91/100 000 person-years (95% CI 4.73 to 5.09), with an annual 1.8% decline (p<0.001). In contrast, the prevalence increased from 64.99/100 000 in 1999 (95% CI 62.04 to 67.93) (0.065%) to 97.04/100 000 in 2012 (95% CI 94.18 to 99.90) (0.097%). SLE was six times more common in women. The peak age of incidence was 50-59 years. There was regional variation in both incidence and prevalence. People of Black Caribbean ethnicity had the highest incidence and prevalence. Alternative definitions of SLE increased (definition 2) or decreased (definition 3) estimates of incidence and prevalence, but similar trends were found.
  
  
  CONCLUSIONS
  The incidence of SLE has been declining but the prevalence has been increasing in the UK in recent years. Age, gender, region and ethnicity are risk factors for SLE. This is the first study to report ethnic differences on the incidence and prevalence of SLE using the CPRD.
authors.affiliation: Division of Rheumatology, Orthopaedics and Dermatology, University of Nottingham, Nottingham, UK Rheumatology Department, Nottingham University Hospitals NHS Trust, Nottingham, UK.
authors.forename: Frances
authors.initials: F
authors.lastname: Rees
authors.affiliation: Division of Rheumatology, Orthopaedics and Dermatology, University of Nottingham, Nottingham, UK.
authors.forename: Michael
authors.initials: M
authors.lastname: Doherty
authors.affiliation: Division of Epidemiology and Public Health, University of Nottingham, Nottingham, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Grainge
authors.affiliation: Arthritis Research UK Primary Care Centre, Keele University, Keele, UK.
authors.forename: Graham
authors.initials: G
authors.lastname: Davenport
authors.affiliation: Division of Rheumatology, Orthopaedics and Dermatology, University of Nottingham, Nottingham, UK Rheumatology Department, Nottingham University Hospitals NHS Trust, Nottingham, UK.
authors.forename: Peter
authors.initials: P
authors.lastname: Lanyon
authors.affiliation: Division of Rheumatology, Orthopaedics and Dermatology, University of Nottingham, Nottingham, UK.
authors.forename: Weiya
authors.initials: W
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D044383:Black People / Q000706:statistics & numerical data; D017691:Caribbean Region / Q000208:ethnology; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D015994:Incidence; D008180:Lupus Erythematosus, Systemic / Q000453:epidemiology* / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012189:Retrospective Studies; D012737:Sex Factors; D006113:United Kingdom / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data; D055815:Young Adult
keywords: Autoimmune Diseases; Epidemiology; Systemic Lupus Erythematosus