Summary of findings 2. Vitamin K antagonists compared to placebo for prevention of venous thromboembolism following total hip or knee replacement or hip fracture repair.
| Vitamin K antagonists compared to placebo for prevention of venous thromboembolism following total hip or knee replacement or hip fracture repair | ||||||
| Patient or population: people requiring prevention of venous thromboembolism following total hip or knee replacement or hip fracture repair Setting: hospital and outpatient setting Intervention: vitamin K antagonists Comparison: placebo | ||||||
| Outcomes | Anticipated absolute effects* (95% CI) | Relative effect (95% CI) | Number of participants (studies) | Quality of the evidence (GRADE) | Comments | |
| Risk with placebo | Risk with vitamin K antagonists | |||||
| Symptomatic VTE (DVT and PE) Treatment duration 28 ‐ 42 days | Study population | OR 0.10 (0.01 to 1.94) | 360 (1 RCT) | ⊕⊕⊕⊝ MODERATE 1 | — | |
| 23 per 1000 | 2 per 1000 (0 to 43) | |||||
| Symptomatic DVT (proximal or distal) Treatment duration 28 ‐ 42 days | Study population | OR 0.13 (0.01 to 2.62) | 360 (1 RCT) | ⊕⊕⊕⊝ MODERATE 1 | — | |
| 17 per 1000 | 2 per 1000 (0 to 43) | |||||
| Symptomatic PE Treatment duration 28 ‐ 42 days | Study population | OR 0.32 (0.01 to 7.84) | 360 (1 RCT) | ⊕⊕⊕⊝ MODERATE 1 | — | |
| 6 per 1000 | 2 per 1000 (0 to 43) | |||||
| Bleeding ‐ major Treatment duration 28 ‐ 42 days | see comment | OR 2.89 (0.12 to 71.31) | 360 (1 RCT) | ⊕⊕⊝⊝ LOW 1 2 | no events recorded in placebo group | |
| Clinically relevant non‐major bleeding Treatment duration 28 ‐ 42 days | see comment | — | — | — | not reported | |
| Minor bleeding Treatment duration 28 ‐ 42 days | see comment | — | — | — | not reported | |
| *The risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI). CI: confidence interval; DVT: deep vein thrombosis; OR: odds ratio; PE: pulmonary embolism; RCT: randomised controlled trial; VTE: venous thromboembolism | ||||||
| GRADE Working Group grades of evidence High quality: We are very confident that the true effect lies close to that of the estimate of the effect Moderate quality: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different Low quality: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect Very low quality: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect | ||||||
1 Downgraded by one level, results from a single study only so heterogeneity could not be assessed 2 Downgraded by one level, number of events small leading to wide CI and imprecision of results