title: Validation of the Oudega diagnostic decision rule for diagnosing deep vein thrombosis in frail older out-of-hospital patients.
abstract: OBJECTIVE
  We aimed to validate the Oudega diagnostic decision rule-which was developed and validated among younger aged primary care patients-to rule-out deep vein thrombosis (DVT) in frail older outpatients.
  
  
  METHODS
  In older patients (>60 years, either community dwelling or residing in nursing homes) with clinically suspected DVT, physicians recorded the score on the Oudega rule and d-dimer test. DVT was confirmed with a composite reference standard including ultrasonography examination and 3-month follow-up. The proportion of patients with a very low probability of DVT according to the Oudega rule (efficiency), and the proportion of patients with symptomatic venous thromboembolism during 3 months follow-up within this 'very low risk' group (failure rate) was calculated.
  
  
  RESULTS
  DVT occurred in 164 (47%) of the 348 study participants (mean age 81 years, 85% residing in nursing homes). The probability of DVT was very low in 69 patients (Oudega score ≤3 points plus a normal d-dimer test; efficiency 20%) of whom four had non-fatal DVT (failure rate 5.8%; 2.3-14%). With a simple revised version of the Oudega rule for older suspected patients, 43 patients had a low risk of DVT (12% of the total population) of whom only one had DVT (failure rate 2.3%; 0.4-12%).
  
  
  CONCLUSIONS
  In older suspected patients, application of the original Oudega rule to exclude DVT resulted in a higher failure rate as compared to previous studies. A revised and simplified Oudega strategy specifically developed for elderly suspected patients resulted in a lower failure rate though at the expense of a lower efficiency.
authors.affiliation: Julius Center for Health Sciences and Primary Care and Department of Geriatrics, University Medical Center Utrecht, Utrecht and Department of Internal Medicine, Diakonessenhuis, Utrecht, The Netherlands. h.j.schouten@umcutrecht.nl.
authors.forename: Henrike J
authors.initials: HJ
authors.lastname: Schouten
authors.affiliation: Department of Geriatrics, University Medical Center Utrecht, Utrecht and.
authors.forename: Huiberdina L
authors.initials: HL
authors.lastname: Koek
authors.affiliation: Julius Center for Health Sciences and Primary Care and.
authors.forename: Ruud
authors.initials: R
authors.lastname: Oudega
authors.affiliation: Julius Center for Health Sciences and Primary Care and.
authors.forename: Johannes J M
authors.initials: JJ
authors.lastname: van Delden
authors.affiliation: Julius Center for Health Sciences and Primary Care and.
authors.forename: Karel G M
authors.initials: KG
authors.lastname: Moons
authors.affiliation: Julius Center for Health Sciences and Primary Care and.
authors.forename: Geert-Jan
authors.initials: GJ
authors.lastname: Geersing
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003661:Decision Support Techniques; D005260:Female; D005500:Follow-Up Studies; D016330:Frail Elderly; D006707:Homes for the Aged; D006801:Humans; D057187:Independent Living; D008297:Male; D009735:Nursing Homes; D011446:Prospective Studies; D015203:Reproducibility of Results; D020246:Venous Thrombosis / Q000175:diagnosis*
keywords: Clinical prediction rule; d-dimer; deep vein thrombosis; diagnosis; elderly; venous thromboembolism.