title: A critical evaluation of venous thromboembolism risk assessment models used in patients with lower limb cast immobilisation.
abstract: BACKGROUND
  There is a recognised link between lower limb cast immobilisation and the development of venous thromboembolism (VTE). Our aim was to assess the diagnostic accuracy of risk assessment models (RAMs) applicable to this patient group. This has not been done before.
  
  
  METHODS
  A literature and guideline review identified five RAMs. They were used to retrospectively risk assess a consecutive series of patients who were diagnosed with symptomatic VTE following lower limb injury treated with a cast (Group I). A case-matched cohort who did not suffer symptomatic VTE (Group II) was also retrospectively risk assessed. The RAMs' diagnostic performance indicators were calculated.
  
  
  RESULTS
  Groups I and II consisted of 21 patients each. There was no significant difference in the mean age or total number of VTE risk factors between Groups I and II (p=.957 and p=.878 respectively). The Plymouth (2010) RAM achieved the highest accuracy (54.8%).
  
  
  CONCLUSIONS
  Each RAM demonstrated significant limitations. Two displayed very limited clinical utility. Three recommended chemical thromboprophylaxis to all patients because they weighted lower limb immobilisation as an absolute risk factor for the development of VTE. Cast immobilisation should not be considered an absolute risk factor when risk assessing patients who all have casts. Prospective evaluation with a larger patient cohort is required.
authors: Cardiff University Medical School, United Kingdom. Electronic address: uw@doctors.org.uk.
authors: Ultan
authors: U
authors: Watson
authors: University Hospital Wales, Cardiff and Vale University Health Board, United Kingdom.
authors: Ben A
authors: BA
authors: Hickey
authors: University Hospital Wales, Cardiff and Vale University Health Board, United Kingdom.
authors: Huw M
authors: HM
authors: Jones
authors: University Hospital Wales, Cardiff and Vale University Health Board, United Kingdom.
authors: Anthony
authors: A
authors: Perera
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D016512:Ankle Injuries / Q000175:diagnosis / Q000628:therapy*; D000925:Anticoagulants / Q000627:therapeutic use*; D002370:Casts, Surgical / Q000009:adverse effects*; D015331:Cohort Studies; D005260:Female; D018409:Foot Injuries / Q000175:diagnosis / Q000628:therapy*; D006801:Humans; D007103:Immobilization / Q000009:adverse effects / Q000379:methods; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011322:Primary Prevention / Q000379:methods; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012737:Sex Factors; D018709:Statistics, Nonparametric; D006113:United Kingdom; D020246:Venous Thrombosis / Q000209:etiology / Q000517:prevention & control*
chemical_list: D000925:Anticoagulants
keywords: Cast; Deep Vein Thrombosis (DVT); Limb immobilisation; Risk Assessment; Thromboprophylaxis; Trauma; Venous Thromboelbolism (VTE)