title: A review of medical records and discharge summary data found moderate to high predictive values of discharge diagnoses of venous thromboembolism during pregnancy and postpartum.
abstract: OBJECTIVE
  To validate the discharge diagnoses of venous thromboembolism during pregnancy and postpartum, we examined the positive predictive value (PPV) of venous thromboembolic (VTE) discharge diagnoses associated with pregnancy or puerperium based on 311 cases registered in a Danish population-based hospital-discharge registry.
  
  
  METHODS
  Medical records and hospital discharge summaries were retrieved and reviewed using a standardized form. Standard and pregnancy-specific codes were used for 147 (49%) and 153 (51%) cases, respectively.
  
  
  RESULTS
  The overall PPV of the selected codes was 87.3% (95% confidence interval [CI]: 83.0-90.9). When focusing on confirmed VTE events in relation to the pregnancy, the overall PPV was 79.3% (95% CI: 74.3-83.8).
  
  
  CONCLUSIONS
  The overall PPVs of pregnancy-related VTE diagnoses were moderate to high. The predictive values varied substantially between the individual codes, however, and not all the registered VTE events occurred in relation to pregnancy. Thus, use of unvalidated registry-based pregnancy-related VTE diagnoses for epidemiological research may lead to biased results.
authors.affiliation: Department of Clinical Biochemistry and Genetics, Section for Thrombosis and Haemostasis, Odense University Hospital, Sdr. Boulevard 29, DK-5000 Odense, Denmark; Department of Clinical Epidemiology, Aarhus University Hospitals, DK-8000, Aarhus C, Denmark.
authors.forename: Torben Bjerregaard
authors.initials: TB
authors.lastname: Larsen
authors.forename: Søren Paaske
authors.initials: SP
authors.lastname: Johnsen
authors.forename: Charlotte Ihlo
authors.initials: CI
authors.lastname: Møller
authors.forename: Helle
authors.initials: H
authors.lastname: Larsen
authors.forename: Henrik Toft
authors.initials: HT
authors.lastname: Sørensen
mesh_terms: D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D038801:International Classification of Diseases; D008499:Medical Records / Q000145:classification / Q000592:standards*; D010351:Patient Discharge / Q000706:statistics & numerical data*; D011237:Predictive Value of Tests; D011247:Pregnancy; D011249:Pregnancy Complications, Cardiovascular / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology*; D011644:Puerperal Disorders / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology*; D011655:Pulmonary Embolism / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology; D012042:Registries / Q000592:standards*; D014600:Utilization Review; D020246:Venous Thrombosis / Q000145:classification / Q000175:diagnosis / Q000453:epidemiology*