title: Bullous pemphigoid and pemphigus vulgaris--incidence and mortality in the UK: population based cohort study.
abstract: OBJECTIVE
  To determine the incidence of and mortality from bullous pemphigoid and pemphigus vulgaris in the United Kingdom.
  
  
  METHODS
  Retrospective historical cohort study.
  
  
  METHODS
  Computerised medical records from the health improvement network, a large population based UK general practice database.
  
  
  METHODS
  Patients with pemphigus vulgaris and bullous pemphigoid diagnostic codes and age, sex, and practice matched controls.
  
  
  METHODS
  Incidence and mortality compared with the control population by calendar period, age group, sex, geographical region, and degree of social deprivation.
  
  
  RESULTS
  869 people with bullous pemphigoid and 138 people with pemphigus vulgaris were identified. The median age at presentation for bullous pemphigoid was 80 (range 23-102) years, and 534 (61%) patients were female. The median age at presentation for pemphigus vulgaris was 71 (21-102) years, and 91 (66%) patients were female. Incidences of bullous pemphigoid and pemphigus vulgaris were 4.3 (95% confidence interval 4.0 to 4.6) and 0.7 (0.6 to 0.8) per 100 000 person years. The incidence of bullous pemphigoid increased over time; the average yearly increase was 17% (incidence rate ratio=1.2, 95% confidence interval 1.1 to 1.2). An average yearly increase in incidence of pemphigus vulgaris of 11% (incidence rate ratio=1.1, 1.0 to 1.2) occurred. The risk of death for patients with bullous pemphigoid was twice as great as for controls (adjusted hazard ratio=2.3, 95% confidence interval 2.0 to 2.7). For pemphigus vulgaris, the risk of death was three times greater than for controls (adjusted hazard ratio=3.3, 2.2 to 5.2).
  
  
  CONCLUSIONS
  Incidences of bullous pemphigoid and pemphigus vulgaris are increasing. The reasons for the changes in incidence are not clearly understood but have implications for identifying causative factors. Both disorders are associated with a high risk of death. Previous estimates may have underestimated the risk of death associated with these diseases.
authors.affiliation: Centre of Evidence-based Dermatology, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH. sinead.langan@nottingham.ac.uk
authors.forename: S M
authors.initials: SM
authors.lastname: Langan
authors.forename: L
authors.initials: L
authors.lastname: Smeeth
authors.forename: R
authors.initials: R
authors.lastname: Hubbard
authors.forename: K M
authors.initials: KM
authors.lastname: Fleming
authors.forename: C J P
authors.initials: CJ
authors.lastname: Smith
authors.forename: J
authors.initials: J
authors.lastname: West
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D010391:Pemphigoid, Bullous / Q000401:mortality*; D010392:Pemphigus / Q000401:mortality*; D012189:Retrospective Studies; D015996:Survival Rate; D006113:United Kingdom / Q000453:epidemiology