Lapidus 2007b.
| Methods | Study design: randomized, controlled, double‐blind trial Method of randomization: not reported Concealment of allocation: not reported Losses to follow‐up: 75 considered non‐evaluable for primary analysis (35 treatment group and 40 in control group), due to: withdrawal of consent (38), technical failure of phlebography (27), refracture or resurgery (4), failure of protocol compliance (3), minor bleeding (1), inconclusive phlebography (1), never received allocated treatment due to DVT before start of treatment (1). Exclusions were evenly divided over the two groups |
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| Participants | Country: Sweden Number randomized: 272; treatment group 136; control group 136 Number reported, included in analysis 1 (assessment using phlebography): 197; treatment group 101; control group 96 Number reported, included in analysis 2 (assessment using phlebography plus color duplex sonography): 226; treatment group 117; control group 109 Age mean (SD): treatment group 49 years (14); control group 48 years (14) Sex (male/female): treatment group 62/74; control group 62/74 Inclusion criteria: age 18 to 75 years, admitted for an acute (0 to 72 hours) ankle fracture and accepted for surgery Exclusion criteria: inability or refusal to give informed consent, ongoing treatment with anticoagulant therapy, known allergy for contrast media, kidney disorder, recent thromboembolic event, recent surgery, known malignancy, current bleeding disorder, pregnancy, treatment with platelet inhibitors, multi‐trauma |
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| Interventions | Treatment group: LMWH dalteparin 5000 units sc once daily until removal of the plaster cast Control group: placebo |
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| Outcomes | Diagnosis of DVT by means of ascending venography | |
| Notes | All patients treated with LMWH one week before randomization | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Method of randomization was not described. Patients were not included when study personnel were off duty. |
| Allocation concealment (selection bias) | Unclear risk | Not reported |
| Blinding of participants and personnel (performance bias) All outcomes | Unclear risk | Study described as double‐blind. Patients were blinded by using identical prefilled syringes. Blinding of personnel was not explicitly described. |
| Blinding of outcome assessment (detection bias) All outcomes | Low risk | Outcome measures were assessed by a radiologist blinded to randomization and previous imaging findings. |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | 75 out of 272 patients were considered non‐evaluable for primary analysis due to withdrawal of consent (38), technical failure of phlebography (27), refracture or resurgery (4), failure of protocol compliance (3), minor bleeding (1), inconclusive phlebography (1), never received allocated treatment due to DVT before start of treatment (1). Exclusions were evenly divided over the two groups. |
| Selective reporting (reporting bias) | Low risk | Primary efficacy, secondary efficacy and any adverse events were assessed and reported |
| Other bias | Low risk | No other bias was detected |