title: Comparison of UK paediatric cardiac surgical performance by analysis of routinely collected data 1984-96: was Bristol an outlier?
abstract: BACKGROUND
  Reports of high mortality after paediatric cardiac surgery at the Bristol Royal Infirmary, UK, led to the establishment of an independent public inquiry. A key question was whether or not the mortality statistics in Bristol were unusual compared with other specialist centres. To answer this question, we did a retrospective analysis of mortality in the UK using two datasets.
  
  
  METHODS
  Data from the UK Cardiac Surgical Register (CSR; January, 1984, to March, 1996) and Hospital Episode Statistics (HES; April, 1991, to December, 1995) were obtained for all 12 major centres in which paediatric cardiac surgery is done in the UK. The main outcome measure was mortality within 30 days of a cardiac surgical procedure. We estimated excess deaths in Bristol using a random-effects model derived from the remaining 11 centres. Additionally, a sensitivity analysis was done and case-mix examined.
  
  
  RESULTS
  For children younger than 1 year, in open operations, the mortality rate in Bristol was around double that of the other centres during 1991-95: within the CSR, there were 19.0 excess deaths (95% interval 2-32) among 43 deaths; and in HES, there were 24.1 excess deaths (12-34) among 41 deaths recorded. There was no strong evidence for excess mortality in Bristol for closed operations or for open operations in children older than 1 year.
  
  
  CONCLUSIONS
  Our results suggest that Bristol was an outlier, and we do not believe that statistical variation, systematic bias in data collection, case-mix, or data quality can explain a divergence in performance of this size.
authors.affiliation: Division of Primary Care and Population Health Sciences, Imperial College School of Medicine, London, UK. p.aylin@ic.ac.uk
authors.forename: P
authors.initials: P
authors.lastname: Aylin
authors.forename: B
authors.initials: B
authors.lastname: Alves
authors.forename: N
authors.initials: N
authors.lastname: Best
authors.forename: A
authors.initials: A
authors.lastname: Cook
authors.forename: P
authors.initials: P
authors.lastname: Elliott
authors.forename: S J
authors.initials: SJ
authors.lastname: Evans
authors.forename: A E
authors.initials: AE
authors.lastname: Lawrence
authors.forename: G D
authors.initials: GD
authors.lastname: Murray
authors.forename: J
authors.initials: J
authors.lastname: Pollock
authors.forename: D
authors.initials: D
authors.lastname: Spiegelhalter
mesh_terms: D000293:Adolescent; D000367:Age Factors; D006348:Cardiac Surgical Procedures / Q000401:mortality*; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D016208:Databases, Factual; D004739:England; D006801:Humans; D007223:Infant; D012042:Registries / Q000706:statistics & numerical data; D012189:Retrospective Studies; D015996:Survival Rate