title: Validation and optimisation of an ICD-10-coded case definition for sepsis using administrative health data.
abstract: OBJECTIVE
  Administrative health data are important for health services and outcomes research. We optimised and validated in intensive care unit (ICU) patients an International Classification of Disease (ICD)-coded case definition for sepsis, and compared this with an existing definition. We also assessed the definition's performance in non-ICU (ward) patients.
  
  
  METHODS
  All adults (aged ≥ 18 years) admitted to a multisystem ICU with general medicosurgical ICU care from one of three tertiary care centres in the Calgary region in Alberta, Canada, between 1 January 2009 and 31 December 2012 were included.
  
  
  METHODS
  Patient medical records were randomly selected and linked to the discharge abstract database. In ICU patients, we validated the Canadian Institute for Health Information (CIHI) ICD-10-CA (Canadian Revision)-coded definition for sepsis and severe sepsis against a reference standard medical chart review, and optimised this algorithm through examination of other conditions apparent in sepsis.
  
  
  METHODS
  Sensitivity (Sn), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) were calculated.
  
  
  RESULTS
  Sepsis was present in 604 of 1001 ICU patients (60.4%). The CIHI ICD-10-CA-coded definition for sepsis had Sn (46.4%), Sp (98.7%), PPV (98.2%) and NPV (54.7%); and for severe sepsis had Sn (47.2%), Sp (97.5%), PPV (95.3%) and NPV (63.2%). The optimised ICD-coded algorithm for sepsis increased Sn by 25.5% and NPV by 11.9% with slightly lowered Sp (85.4%) and PPV (88.2%). For severe sepsis both Sn (65.1%) and NPV (70.1%) increased, while Sp (88.2%) and PPV (85.6%) decreased slightly.
  
  
  CONCLUSIONS
  This study demonstrates that sepsis is highly undercoded in administrative data, thus under-ascertaining the true incidence of sepsis. The optimised ICD-coded definition has a higher validity with higher Sn and should be preferentially considered if used for surveillance purposes.
authors.affiliation: Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Rachel J
authors.initials: RJ
authors.lastname: Jolley
authors.affiliation: Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada O'Brien Institute for Public Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Hude
authors.identifier: http://orcid.org/0000-0002-7848-7256
authors.initials: H
authors.lastname: Quan
authors.affiliation: Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada O'Brien Institute for Public Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Jetté
authors.affiliation: Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Keri Jo
authors.initials: KJ
authors.lastname: Sawka
authors.affiliation: Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Lucy
authors.initials: L
authors.lastname: Diep
authors.affiliation: Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Jade
authors.initials: J
authors.lastname: Goliath
authors.affiliation: Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada Department of Surgery, Cumming School of Medicine, University of Calgary, Calgary, Canada Department of Critical Care Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Roberts
authors.affiliation: Department of Critical Care Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada Snyder Institute of Chronic Diseases, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Bryan G
authors.initials: BG
authors.lastname: Yipp
authors.affiliation: Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada Department of Critical Care Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada Snyder Institute of Chronic Diseases, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Doig
mesh_terms: D000368:Aged; D000465:Algorithms; D002170:Canada; D059019:Clinical Coding / Q000592:standards*; D016208:Databases, Factual; D005260:Female; D006760:Hospitalization; D006801:Humans; D007362:Intensive Care Units / Q000458:organization & administration*; D038801:International Classification of Diseases; D008297:Male; D008499:Medical Records / Q000592:standards*; D008875:Middle Aged; D010351:Patient Discharge; D012680:Sensitivity and Specificity; D018805:Sepsis / Q000175:diagnosis*; D012720:Severity of Illness Index; D062606:Tertiary Care Centers
keywords: Administrative Data; Diagnosis Validation; International Classification of Disease; Patient Care/Classification; Sepsis