title: Burden of illness in venous thromboembolism in critical care: a multicenter observational study.
abstract: OBJECTIVE
  The frequency of clinically diagnosed venous thromboembolism (VTE) including deep venous thrombosis (DVT) and pulmonary embolism (PE) in medical-surgical critically ill patients is unclear. The objectives of this study were to estimate the prevalence and incidence of radiologically confirmed DVT and PE in medical-surgical intensive care unit (ICU) patients and to determine the impact of prophylaxis on the frequency of these events.
  
  
  METHODS
  In a retrospective observational cohort study in 12 adult ICUs, we identified prevalent cases (diagnosed in the 24 hours preceding ICU admission up to 48 hours post-ICU admission) and incident cases (diagnosed 48 hours or more after ICU admission and up to 8 weeks after ICU discharge) of upper or lower limb DVT or PE. Deep venous thrombosis was diagnosed by compression ultrasound or venogram. Each DVT was classified as clinically suspected or not clinically suspected in that the latter was diagnosed by scheduled screening ultrasonography. Pulmonary embolism was diagnosed by ventilation-perfusion lung scan, computed tomography pulmonary angiography, echocardiography, electrocardiography, or autopsy.
  
  
  RESULTS
  Among 12,338 patients, 252 (2.0%) patients had radiologically confirmed DVT or PE and another 47 (0.4%) had possible DVT or PE. Prevalent DVTs were diagnosed in 0.4% (95% confidence interval [CI], 0.3%-0.5%) of patients and prevalent PEs were diagnosed in 0.4% (95% CI, 0.3%-0.6%). Incident DVTs were diagnosed in 1.0% (95% CI, 0.8%-1.2%) of patients, and incident PEs were diagnosed in 0.5% (95% CI, 0.4%-0.6%). Of patients with incident VTE, 65.8% of cases occurred despite receipt of thromboprophylaxis for at least 80% of their days in ICU. The median (interquartile range) ICU length of stay was similar for patients with DVT (7 [3-17]) and PE (5 [2-8]). For all patients with VTE, ICU mortality was 16.7% (95% CI, 12.0%-21.3%) and hospital mortality was 28.5% (95% CI, 22.8%-34.1%).
  
  
  CONCLUSIONS
  Venous thromboembolism appears to be an apparently infrequent, but likely underdiagnosed problem, occurring among patients receiving prophylaxis. Findings suggest the need for increased suspicion among clinicians, renewed efforts at thromboprophylaxis, and evaluation of superior prevention strategies.
authors.affiliation: Department of Medicine, University of Ottawa, Canada K1Y 4E9.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Patel
authors.forename: Deborah J
authors.initials: DJ
authors.lastname: Cook
authors.forename: Maureen O
authors.initials: MO
authors.lastname: Meade
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Griffith
authors.forename: Geeta
authors.initials: G
authors.lastname: Mehta
authors.forename: Graeme M
authors.initials: GM
authors.lastname: Rocker
authors.forename: John C
authors.initials: JC
authors.lastname: Marshall
authors.forename: Rick
authors.initials: R
authors.lastname: Hodder
authors.forename: Claudio M
authors.initials: CM
authors.lastname: Martin
authors.forename: Daren K
authors.initials: DK
authors.lastname: Heyland
authors.forename: Sharon
authors.initials: S
authors.lastname: Peters
authors.forename: John
authors.initials: J
authors.lastname: Muscedere
authors.forename: Mark
authors.initials: M
authors.lastname: Soth
authors.forename: Nicole
authors.initials: N
authors.lastname: Campbell
authors.forename: Gordon H
authors.initials: GH
authors.lastname: Guyatt
mesh_terms: D000925:Anticoagulants / Q000627:therapeutic use; D002170:Canada / Q000453:epidemiology; D005260:Female; D006801:Humans; D015994:Incidence; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011655:Pulmonary Embolism / Q000453:epidemiology* / Q000517:prevention & control* / Q000628:therapy; D012189:Retrospective Studies; D020246:Venous Thrombosis / Q000453:epidemiology* / Q000517:prevention & control* / Q000628:therapy
chemical_list: D000925:Anticoagulants