title: Systematic review of discharge coding accuracy.
abstract: BACKGROUND
  Routinely collected data sets are increasingly used for research, financial reimbursement and health service planning. High quality data are necessary for reliable analysis. This study aims to assess the published accuracy of routinely collected data sets in Great Britain.
  
  
  METHODS
  Systematic searches of the EMBASE, PUBMED, OVID and Cochrane databases were performed from 1989 to present using defined search terms. Included studies were those that compared routinely collected data sets with case or operative note review and those that compared routinely collected data with clinical registries.
  
  
  RESULTS
  Thirty-two studies were included. Twenty-five studies compared routinely collected data with case or operation notes. Seven studies compared routinely collected data with clinical registries. The overall median accuracy (routinely collected data sets versus case notes) was 83.2% (IQR: 67.3-92.1%). The median diagnostic accuracy was 80.3% (IQR: 63.3-94.1%) with a median procedure accuracy of 84.2% (IQR: 68.7-88.7%). There was considerable variation in accuracy rates between studies (50.5-97.8%). Since the 2002 introduction of Payment by Results, accuracy has improved in some respects, for example primary diagnoses accuracy has improved from 73.8% (IQR: 59.3-92.1%) to 96.0% (IQR: 89.3-96.3), P= 0.020.
  
  
  CONCLUSIONS
  Accuracy rates are improving. Current levels of reported accuracy suggest that routinely collected data are sufficiently robust to support their use for research and managerial decision-making.
authors.affiliation: Department of Surgery,  Imperial College, St Mary's Hospital, Praed Street, W21NY London,  UK.
authors.forename: E M
authors.initials: EM
authors.lastname: Burns
authors.forename: E
authors.initials: E
authors.lastname: Rigby
authors.forename: R
authors.initials: R
authors.lastname: Mamidanna
authors.forename: A
authors.initials: A
authors.lastname: Bottle
authors.forename: P
authors.initials: P
authors.lastname: Aylin
authors.forename: P
authors.initials: P
authors.lastname: Ziprin
authors.forename: O D
authors.initials: OD
authors.lastname: Faiz
mesh_terms: D059019:Clinical Coding / Q000592:standards* / Q000706:statistics & numerical data; D016206:Databases, Bibliographic; D006801:Humans; D010351:Patient Discharge / Q000592:standards* / Q000706:statistics & numerical data; D012042:Registries; D015203:Reproducibility of Results; D013222:State Medicine / Q000592:standards* / Q000706:statistics & numerical data; D006113:United Kingdom