title: Is development of postoperative venous thromboembolism related to thromboprophylaxis use? A case-control study in the Veterans Health Administration.
abstract: BACKGROUND
  Observational studies continue to report thromboprophylaxis underuse for postoperative pulmonary embolism/deep vein thrombosis (pPE/DVT) despite the long-standing existence of prevention guidelines. However, data are limited on whether thromboprophylaxis use differs between patients developing pPE/DVT versus those who do not or on why prophylaxis is withheld.
  
  
  METHODS
  Administrative data (2002-2007) from 28 Veterans Health Administration hospitals were screened for discharges with (1) pPE/DVT as flagged by the Agency for Healthcare Research and Quality (AHRQ) Patient Safety Indicator software and (2) pharmacoprophylaxis-recommended procedures, and the medical records were reviewed to ascertain true pPE/DVT cases. Controls were selected by matching cases by hospital, age, sex, diagnosis-related group, and predicted probability for developing pPE/DVT, and who underwent a pharmacoprophylaxis-recommended procedure. Records were assessed for "appropriate pharmacoprophylaxis use," defined primarily per American College of Chest Physicians (ACCP) guidelines, and reasons for anticoagulant nonuse.
  
  
  RESULTS
  The 116 case-control pairs were similar in terms of demographics, surgery type, ACCP risk category, and appropriate pharmacoprophylaxis rates overall. Of the highest-risk patients, respective pharmacoprophylaxis rates among cases and controls were 88% versus 92% among hip/knee replacements and 31% versus 48% among cancer patients. Of the cases and controls who did not receive appropriate pharmacoprophylaxis, only about 25% had documented contraindications. Reviewers identified contraindications in 14% of cases and 9% of controls.
  
  
  CONCLUSIONS
  Similarities in preventive pPE/DVT practice between cases and controls suggest that pPE/DVTs occur despite implementation of guideline-adherent practices.
authors.affiliation: US Department of Veterans Affairs, Center for Health Quality, Outcomes and Economic Research, Bedford VA Hospital, Bedford, Massachusetts, USA. amb@bu.edu
authors.forename: Ann M
authors.initials: AM
authors.lastname: Borzecki
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Cowan
authors.forename: Marisa
authors.initials: M
authors.lastname: Cevasco
authors.forename: Marlena H
authors.initials: MH
authors.lastname: Shin
authors.forename: Michael
authors.initials: M
authors.lastname: Shwartz
authors.forename: Kamal
authors.initials: K
authors.lastname: Itani
authors.forename: Amy K
authors.initials: AK
authors.lastname: Rosen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000008:administration & dosage*; D057286:Electronic Health Records / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology / Q000517:prevention & control*; D011184:Postoperative Period; D011655:Pulmonary Embolism / Q000453:epidemiology / Q000517:prevention & control*; D012307:Risk Factors; D012959:Socioeconomic Factors; D014481:United States / Q000453:epidemiology; D014493:United States Department of Veterans Affairs / Q000706:statistics & numerical data*; D054556:Venous Thromboembolism / Q000453:epidemiology / Q000209:etiology / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants