Table A3

Individualised risk assessment

Author, date and countryPatient groupStudy type (level of evidence)OutcomesKey resultsStudy weaknesses
Riou et al, 2007, France3698 adult patients presenting to the ED with isolated non-surgical lower limb injury below the knee. 2761 (75%) completed follow-up and underwent full leg compression ultrasound of the affected limbProspective multicentre observational cohort (level of evidence 2b)Incidence of VTE after removal of immobilisation6.4% (95% CI 5.5% to 7.4%)ED physicians were left to decide on the type of VTE prophylaxis: over 60% patients received some form of pharmacological prophylaxis. This sample is thus not truly reflective of an untreated ED population. Only 75% ultrasound follow-up rate (2761 patients)
Predictive variables of VTE development after multivariate analysisAge >50 (OR 3.14, p<0.0001), rigid immobilisation (OR 2.70, p<0.0001), non-weight-bearing status (OR 4.11, p=0.0015) and severe injury (OR 1.88, p=0.0002)
Eisele et al, 1998, Germany731 outpatients with recent injury or surgery of the leg/pelvis. All patients underwent pre-ultrasonic and post-ultrasonic investigations for DVT in the lower extremitiesProspective interventional cohort. A subjective scoring system to ascertain risk of VTE within the cohort was created based on previous research and expert opinion. This scoring system was applied to each patient with a binary risk outcome and prescription of prophylaxis in tandem with a ‘high-risk’ score (level of evidence 4)Incidence of VTE in patients deemed to be at ‘high risk’ of development4%Scoring system was not independently derived from original research (no mention of risk stratification/risk ratios for independent variables/derivation set). All patients deemed to be at high risk were treated with LMWH/UFH. No attempt at external validation. No CIs given. No subgroup analysis to identify risk factors for those developing DVT in the conservatively treated cohort
Incidence of VTE in patients deemed to be at ‘low risk’ of development0.6%
Kujath et al, 1993, Germany253 ambulatory outpatients with lower limb injuries treated with immobilisation by plaster castProspective randomised controlled trial. 126 patients randomised to LMWH and 127 receiving no thromboembolic prophylaxis. Data on risk factors collated and analysed to determine quantifiable risk in relation to development of thrombosis (level of evidence 2b)Incidence of VTE in therapeutic arm4.8%No multivariate analysis performed on individual risk factors: the presence of each risk factor was compared in patients with and without thrombosis to evaluate statistical significance. Included patients undergoing surgical intervention at a later date. 5 patients had DVT on ultrasound with failed phlebographic confirmation
Incidence of VTE in conservative arm16.5%
Number of average risk factors present in patients developing DVT1.96
Giannadakis et al, 2000, Germany178 ambulatory patients immobilised in plaster casts for lower limb injuries deemed to be at low risk of thromboembolic disease, and therefore prescribed no pharmacological prophylaxis. Most of these patients had a fibular ligament injury (144), with the remaining 34 patients having metatarsal fractures (16), ankle fractures (11), calcaneal fractures (4) and talar fractures (3)Prospective observational cohort. All patients were clinically examined and underwent colour-coded duplex sonography for detection of DVT after removal of the cast at the end of the immobilisation period. Confirmation of DVT was performed by contrast venography when suspected on ultrasound (level 2b)Incidence of lower limb DVT within the cohort1.1% (95% CI 0% to 4.4%)Very low incidence of fractures within the cohort and no subgroup analysis. ‘Low-risk’ cohort defined by local guidance rather than validated decision tool. Investigation of pulmonary VTE based on clinical suspicion only. Limited data on method of duplex assessment, including objective criteria for diagnosis of calf thrombi
Incidence of clinically suspected pulmonary VTE within the cohort0%
  • DVT, deep vein thrombosis; ED, emergency department; LMWH, low molecular weight heparin; VTE, venous thromboembolism.