Individual risk factors predictive of venous thromboembolism in patients with temporary lower limb immobilization due to injury: a systematic review

Abstract

Essentials Thromboprophylaxis after lower limb injury is often based on complex risk stratification. Our systematic review identified variables predicting venous thromboembolism (VTE) in this group. Age and injury type were commonly reported to increase the odds of VTE (odds ratio 1.5–3.48). We found limited evidence to support the use of other risk factors within prediction models. Summary Background Patients immobilized after lower limb injury are at risk of venous thromboembolism ( VTE ). There is international variation in the use of thromboprophylaxis for such patients. Risk‐based strategies have been adopted to aid decision making in many settings. The accuracy of these strategies is unclear. Objectives A systematic review was undertaken to identify all individual patient‐identifiable risk factors linked to any VTE outcome following lower limb immobilization. Methods Several electronic databases were searched from inception to May 2017. Any studies that included a measurement of VTE as a patient outcome in adults requiring temporary immobilization (e.g. leg cast or brace in an ambulatory setting) for an isolated lower limb injury and reported risk factor variables were included. Descriptive statistics and thematic analysis were used to synthesize the evidence. Results Our database search returned 4771 citations, of which 15 studies reporting outcome data on 80 678 patients were eligible for analysis. Risk‐factor associations were reported through regression analyses, non‐parametric tests and descriptive statistics. All studies were assessed as at moderate or serious risk of bias using the ROBINS ‐I risk of bias tool. Advancing age and injury type were the only individual risk factors demonstrating a reproducible association with increased symptomatic and/or asymptomatic VTE rates. Several risk factors currently used in scoring tools did not appear to be robustly evaluated for subsequent association with VTE within these studies. Conclusions Clinicians should be aware of the limited evidence to support individual risk factors in guiding thromboprophylaxis use for this patient cohort.

Early mobilization does not reduce the risk of deep venous thrombosis after Achilles tendon rupture: a randomized controlled trial

“…Moreover, the observation that the risk of DVT increased by 7% per each increasing year of age, is confirmed by earlier studies [1,11,20]. The finding also indicates that older age together with BMI should be considered while deciding DVT preventive interventions during leg immobilization [11,20,22]. This is the first prospective randomized study to study DVT rate during EFM.…”

Thromboprophylaxis in lower limb immobilisation after injury (TiLLI)

“…BMI was the third most consistent individual risk highlighted, although overall results were conflicting. A total of 12 other risk factors analysed did not demonstrate any consistency in association with VTE across the dataset 39. A subsequent publication supports our findings, reporting injury pattern, family history and BMI to be the individual risk factors most associated with VTE risk, among the POT CAST trial cohort 40…”

What’s new in VTE risk and prevention in orthopedic surgery

“…The importance of previous VTE as a risk factor was further emphasized by a recent report from the MEGA study, which showed that patients with previous VTE who subsequently required lower leg casting had a 4.5‐fold risk of developing recurrent VTE, which translated to an absolute risk of 3.2% within 3 months . A meta‐analysis of 15 studies reporting outcome data on 80 678 patients found that only advancing age and injury type were predictive of VTE and cautioned against using individual risk factors to guide the use of thromboprophylaxis . Risk assessment models have been developed to predict risk of VTE after lower leg casting or trauma, including the Leiden‐Thrombosis Risk Prediction for Patients With Cast Immobilization (L‐TRiP[cast])score and the Trauma, Immobilization and Patients’ characteristics (TIP) score .…”

“…Recently, a 2019 meta‐analysis reviewed 13 randomized trials (6857 participants) that compared thromboprophylactic agents to each other or to no pharmacologic prophylaxis to prevent VTE in patients with temporary lower‐limb immobilization after injury . Across trials, LMWH reduced the risk of symptomatic DVT (odds ratio [OR], 0.40; 95% credible interval [CrI], 0.12‐0.99) and PE (OR, 0.17; 95% CrI, 0.01‐0.88) compared to no treatment, and fondaparinux reduced the risk of symptomatic DVT (OR, 0.10; 95% CrI, 0.01‐0.94) but not PE (OR, 0.47; 95% CrI, 0.01‐9.54).…”

“…35 A meta-analysis of 15 studies reporting outcome data on 80 678 patients found that only advancing age and injury type were predictive of VTE and cautioned against using individual risk factors to guide the use of thromboprophylaxis. 36 However, prospective validation, ideally with implementation studies, are required.…”