Middeldorp, Saskia

Background Hereditary and acquired thrombophilia are risk factors for venous thromboembolism (VTE). Whether testing helps guide management decisions is controversial. Objective These evidence-based guidelines from the American Society of Hematology (ASH) intend to support decision making about thrombophilia testing. Methods ASH formed a multidisciplinary guideline panel covering clinical and methodological expertise and minimizing bias from conflicts of interest. The McMaster University GRADE Centre provided logistical support, performed systematic reviews, and created evidence profiles and evidence-to-decision tables. The Grading of Recommendations Assessment, Development, and Evaluation approach (GRADE) was used. Recommendations were subject to public comment. Results The panel agreed on 23 recommendations regarding thrombophilia testing and associated management. Nearly all recommendations are based on very low certainty in the evidence due to modeling assumptions. Conclusions The panel issued a strong recommendation against testing the general population before starting combined oral contraceptives (COCs) and conditional recommendations for thrombophilia testing in the following scenarios: (a) patients with VTE associated with nonsurgical major transient or hormonal risk factors; (b) patients with cerebral or splanchnic venous thrombosis, in settings where anticoagulation would otherwise be discontinued; (c) individuals with a family history of antithrombin, protein C, or protein S deficiency when considering thromboprophylaxis for minor provoking risk factors and for guidance to avoid COCs/hormone replacement therapy; (d) pregnant women with a family history of high-risk thrombophilia types; and (e) patients with cancer at low or intermediate risk of thrombosis and with a family history of VTE. For all other questions, the panel provided conditional recommendations against testing for thrombophilia.

Abstract Direct oral anticoagulants (DOACs) are an emerging treatment option for patients with cancer and acute venous thromboembolism (VTE), but studies have reported inconsistent results. This systematic review and meta-analysis compared the efficacy and safety of DOACs and low-molecular-weight heparins (LMWHs) in these patients. MEDLINE, Embase, the Cochrane Central Register of Controlled Trials, and conference proceedings were searched to identify relevant randomized controlled trials. Additional data were obtained from the original authors to homogenize definitions for all study outcomes. The primary efficacy and safety outcomes were recurrent VTE and major bleeding, respectively. Other outcomes included the composite of recurrent VTE and major bleeding, clinically relevant nonmajor bleeding (CRNMB), and all-cause mortality. Summary relative risks (RRs) were calculated in a random effects meta-analysis. In the primary analysis comprising 2607 patients, the risk of recurrent VTE was nonsignificantly lower with DOACs than with LMWHs (RR, 0.68; 95% CI, 0.39-1.17). Conversely, the risks of major bleeding (RR, 1.36; 95% CI, 0.55-3.35) and CRNMB (RR, 1.63; 95% CI, 0.73-3.64) were nonsignificantly higher. The risk of the composite of recurrent VTE or major bleeding was nonsignificantly lower with DOACs than with LMWHs (RR, 0.86; 95% CI, 0.60-1.23). Mortality was comparable in both groups (RR, 0.96; 95% CI, 0.68-1.36). Findings were consistent during the on-treatment period and in those with incidental VTE. In conclusion, DOACs are an effective treatment option for patients with cancer and acute VTE, although caution is needed in patients at high risk of bleeding.