Iberoamerican Cochrane Centre, CIBERESP-IIB Sant Pau, Barcelona, 08041, Spain.
BMC Pregnancy Childbirth. 2012 May 30;12:40. doi: 10.1186/1471-2393-12-40.
Pregnant women with prior venous thromboembolism (VTE) are at risk of recurrence. Low molecular weight heparin (LWMH) reduces the risk of pregnancy-related VTE. LMWH prophylaxis is, however, inconvenient, uncomfortable, costly, medicalizes pregnancy, and may be associated with increased risks of obstetrical bleeding. Further, there is uncertainty in the estimates of both the baseline risk of pregnancy-related recurrent VTE and the effects of antepartum LMWH prophylaxis. The values and treatment preferences of pregnant women, crucial when making recommendations for prophylaxis, are currently unknown. The objective of this study is to address this gap in knowledge.
We will perform a multi-center cross-sectional interview study in Canada, USA, Norway and Finland. The study population will consist of 100 women with a history of lower extremity deep vein thrombosis (DVT) or pulmonary embolism (PE), and who are either pregnant, planning pregnancy, or may in the future consider pregnancy (women between 18 and 45 years). We will exclude individuals who are on full dose anticoagulation or thromboprophylaxis, who have undergone surgical sterilization, or whose partners have undergone vasectomy. We will determine each participant's willingness to receive LMWH prophylaxis during pregnancy through direct choice exercises based on real life and hypothetical scenarios, preference-elicitation using a visual analog scale ("feeling thermometer"), and a probability trade-off exercise. The primary outcome will be the minimum reduction (threshold) in VTE risk at which women change from declining to accepting LMWH prophylaxis. We will explore possible determinants of this choice, including educational attainment, the characteristics of the women's prior VTE, and prior experience with LMWH. We will determine the utilities that women place on the burden of LMWH prophylaxis, pregnancy-related DVT, pregnancy-related PE and pregnancy-related hemorrhage. We will generate a "personalized decision analysis" using participants' utilities and their personalized risk of recurrent VTE as inputs to a decision analytic model. We will compare the personalized decision analysis to the participant's stated choice.
The preferences of pregnant women at risk of VTE with respect to the use of antithrombotic therapy remain unexplored. This research will provide explicit, quantitative expressions of women's valuations of health states related to recurrent VTE and its prevention with LMWH. This information will be crucial for both guideline developers and for clinicians.
有静脉血栓栓塞症 (venous thromboembolism, VTE) 病史的孕妇有复发的风险。低分子肝素 (low molecular weight heparin, LMWH) 可降低妊娠相关 VTE 的风险。然而，LMWH 预防措施不方便、不舒服、成本高、使妊娠医学化，并且可能与产科出血风险增加有关。此外，妊娠相关复发性 VTE 的基线风险和产前 LMWH 预防的效果的估计值都不确定。在提出预防建议时，孕妇的价值观和治疗偏好至关重要，但目前尚不清楚这些偏好。本研究旨在解决这一知识空白。
我们将在加拿大、美国、挪威和芬兰进行一项多中心横断面访谈研究。研究人群将包括 100 名有下肢深静脉血栓形成 (deep vein thrombosis, DVT) 或肺栓塞 (pulmonary embolism, PE) 病史的孕妇、计划怀孕或未来可能考虑怀孕的女性（18 至 45 岁）。我们将排除正在接受全剂量抗凝或血栓预防治疗、已行绝育手术或其伴侣已行输精管切除术的个体。我们将通过基于现实生活和假设场景的直接选择练习、使用视觉模拟量表（“感觉温度计”）进行偏好 elicitation 和概率权衡练习来确定每位参与者在怀孕期间接受 LMWH 预防的意愿。主要结局将是女性从拒绝转为接受 LMWH 预防的最小 VTE 风险降低（阈值）。我们将探讨这种选择的可能决定因素，包括教育程度、女性既往 VTE 的特征以及既往 LMWH 治疗的经验。我们将确定女性对 LMWH 预防的负担、妊娠相关 DVT、妊娠相关 PE 和妊娠相关出血的效用。我们将使用参与者的效用及其复发性 VTE 的个性化风险作为输入，为决策分析模型生成“个性化决策分析”。我们将比较个性化决策分析与参与者的既定选择。
有 VTE 风险的孕妇对使用抗血栓治疗的偏好仍未得到探索。这项研究将提供与复发 VTE 及其用 LMWH 预防相关的健康状况的明确、定量表达。这些信息对于指南制定者和临床医生都至关重要。
