title: Disease identification based on ambulatory drugs dispensation and in-hospital ICD-10 diagnoses: a comparison.
abstract: BACKGROUND
  Pharmacy-based case mix measures are an alternative source of information to the relatively scarce outpatient diagnoses data. But most published tools use national drug nomenclatures and offer no head-to-head comparisons between drugs-related and diagnoses-based categories. The objective of the study was to test the accuracy of drugs-based morbidity groups derived from the World Health Organization Anatomical Therapeutic Chemical Classification of drugs by checking them against diagnoses-based groups.
  
  
  METHODS
  We compared drugs-based categories with their diagnoses-based analogues using anonymous data on 108,915 individuals insured with one of four companies. They were followed throughout 2005 and 2006 and hospitalized at least once during this period. The agreement between the two approaches was measured by weighted kappa coefficients. The reproducibility of the drugs-based morbidity measure over the 2 years was assessed for all enrollees.
  
  
  RESULTS
  Eighty percent used a drug associated with at least one of the 60 morbidity categories derived from drugs dispensation. After accounting for inpatient under-coding, fifteen conditions agreed sufficiently with their diagnoses-based counterparts to be considered alternative strategies to diagnoses. In addition, they exhibited good reproducibility and allowed prevalence estimates in accordance with national estimates. For 22 conditions, drugs-based information identified accurately a subset of the population defined by diagnoses.
  
  
  CONCLUSIONS
  Most categories provide insurers with health status information that could be exploited for healthcare expenditure prediction or ambulatory cost control, especially when ambulatory diagnoses are not available. However, due to insufficient concordance with their diagnoses-based analogues, their use for morbidity indicators is limited.
authors.affiliation: Institute of Social and Preventive Medicine (IUMSP), University Hospital Center and Faculty of Biology and Medicine, Biopole 2, Route de la Corniche 10, 1010, Lausanne, Switzerland. patricia.halfon@chuv.ch.
authors.forename: Patricia
authors.initials: P
authors.lastname: Halfon
authors.forename: Yves
authors.initials: Y
authors.lastname: Eggli
authors.forename: Anne
authors.initials: A
authors.lastname: Decollogny
authors.forename: Erol
authors.initials: E
authors.lastname: Seker
mesh_terms: D000553:Ambulatory Care / Q000706:statistics & numerical data*; D003953:Diagnosis-Related Groups / Q000706:statistics & numerical data; D006304:Health Status; D006801:Humans; D007297:Inpatients / Q000706:statistics & numerical data; D007348:Insurance, Health / Q000706:statistics & numerical data; D038801:International Classification of Diseases / Q000706:statistics & numerical data*; D015233:Models, Statistical; D009017:Morbidity; D055553:Prescription Drugs / Q000145:classification / Q000627:therapeutic use*; D013557:Switzerland / Q000453:epidemiology
chemical_list: D055553:Prescription Drugs