title: Predictive value of the present-on-admission indicator for hospital-acquired venous thromboembolism.
abstract: BACKGROUND
  Hospital-acquired venous thromboembolic (HA-VTE) events are an important, preventable cause of morbidity and death, but accurately identifying HA-VTE events requires labor-intensive chart review. Administrative diagnosis codes and their associated "present-on-admission" (POA) indicator might allow automated identification of HA-VTE events, but only if VTE codes are accurately flagged "not present-on-admission" (POA=N). New codes were introduced in 2009 to improve accuracy.
  
  
  METHODS
  We identified all medical patients with at least 1 VTE "other" discharge diagnosis code from 5 academic medical centers over a 24-month period. We then sampled, within each center, patients with VTE codes flagged POA=N or POA=U (insufficient documentation) and POA=Y or POA=W (timing clinically uncertain) and abstracted each chart to clarify VTE timing. All events that were not clearly POA were classified as HA-VTE. We then calculated predictive values of the POA=N/U flags for HA-VTE and the POA=Y/W flags for non-HA-VTE.
  
  
  RESULTS
  Among 2070 cases with at least 1 "other" VTE code, we found 339 codes flagged POA=N/U and 1941 flagged POA=Y/W. Among 275 POA=N/U abstracted codes, 75.6% (95% CI, 70.1%-80.6%) were HA-VTE; among 291 POA=Y/W abstracted events, 73.5% (95% CI, 68.0%-78.5%) were non-HA-VTE. Extrapolating from this sample, we estimated that 59% of actual HA-VTE codes were incorrectly flagged POA=Y/W. POA indicator predictive values did not improve after new codes were introduced in 2009.
  
  
  CONCLUSIONS
  The predictive value of VTE events flagged POA=N/U for HA-VTE was 75%. However, sole reliance on this flag may substantially underestimate the incidence of HA-VTE.
authors.affiliation: *Department of Medicine, Division of Hospital Medicine, UCSF, San Francisco †Department of Medicine, Division of Hospital Medicine, UCSD, San Diego ‡Department of Medicine, UCLA, Los Angeles §Division of General Internal Medicine, Department of Medicine ∥Department of Medicine, UCI, Irvine ¶Department of Medicine #Division of General Internal Medicine, Department of Medicine, UCD, Davis, CA.
authors.forename: Raman R
authors.initials: RR
authors.lastname: Khanna
authors.forename: Sharon B
authors.initials: SB
authors.lastname: Kim
authors.forename: Ian
authors.initials: I
authors.lastname: Jenkins
authors.forename: Robert
authors.initials: R
authors.lastname: El-Kareh
authors.forename: Nasim
authors.initials: N
authors.lastname: Afsarmanesh
authors.forename: Alpesh
authors.initials: A
authors.lastname: Amin
authors.forename: Heather
authors.initials: H
authors.lastname: Sand
authors.forename: Andrew
authors.initials: A
authors.lastname: Auerbach
authors.forename: Catherine Y
authors.initials: CY
authors.lastname: Chia
authors.forename: Gregory
authors.initials: G
authors.lastname: Maynard
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Romano
authors.forename: Richard H
authors.initials: RH
authors.lastname: White
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004282:Documentation / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010343:Patient Admission / Q000706:statistics & numerical data*; D011237:Predictive Value of Tests; D054556:Venous Thromboembolism / Q000453:epidemiology*; D055815:Young Adult