Validation and optimisation of an ICD-10-coded case definition for sepsis using administrative health data

• Published in: BMJ open Vol. 5; no. 12; p. e009487
• Main Authors: Jolley, Rachel J, Quan, Hude, Jetté, Nathalie, Sawka, Keri Jo, Diep, Lucy, Goliath, Jade, Roberts, Derek J, Yipp, Bryan G, Doig, Christopher J
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group LTD 01.01.2015; BMJ Publishing Group
• Subjects: Abdomen; Aged; Algorithms; Blood pressure; Canada; Classification; Clinical Coding - standards; Codes; Creatinine; Databases, Factual; Female; Health services; Hospitalization; Hospitals; Humans; Hypotension; Infections; Intensive Care; Intensive Care Units - organization & administration; International Classification of Diseases; Male; Medical records; Medical Records - standards; Middle Aged; Patient Discharge; Patients; Personal health; Sensitivity and Specificity; Sepsis; Sepsis - diagnosis; Severity of Illness Index; Tertiary Care Centers; Thoracic surgery; Variables; Canada; Alberta Canada; Sepsis; Diagnosis Validation; Administrative Data; International Classification of Disease; Patient Care/Classification
• ISSN: 2044-6055; 2044-6055
• DOI: 10.1136/bmjopen-2015-009487

ObjectiveAdministrative 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.Setting and participantsAll 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.Research designPatient 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.MeasuresSensitivity (Sn), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) were calculated.ResultsSepsis 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.ConclusionsThis 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.