Influence of the CYP4F2 polymorphism on the risk of hemorrhagic complications in coumarin-treated patients

Oral anticoagulants: a systematic overview of reviews on efficacy and safety, genotyping, self-monitoring, and stakeholder experiences

BACKGROUND

This systematic overview was commissioned by England's Department of Health and Social Care (DHSC) to assess the evidence on direct (previously 'novel') oral anticoagulants (OACs), compared with usual care, in adults, to prevent stroke related to atrial fibrillation (AF), and to prevent and treat venous thromboembolism (VTE). Specifically, to assess efficacy and safety, genotyping, self-monitoring, and patient and clinician experiences of OACs.

METHODS

We searched MEDLINE, Embase, ASSIA, and CINAHL, in October, 2017, updated in November 2021. We included systematic reviews, published from 2014, in English, assessing OACs, in adults. We rated review quality using AMSTAR2 or the JBI checklist. Two reviewers extracted and synthesised the main findings from the included reviews.

RESULTS

We included 49 systematic reviews; one evaluated efficacy, safety, and cost-effectiveness, 17 assessed genotyping, 23 self-monitoring or adherence, and 15 experiences (seven assessed two topics). Generally, the direct OACs, particularly apixaban (5 mg twice daily), were more effective and safer than warfarin in preventing AF-related stroke. For VTE, there was little evidence of differences in efficacy between direct OACs and low-molecular-weight heparin (prevention), warfarin (treatment), and warfarin or aspirin (secondary prevention). The evidence suggested that some direct OACs may reduce the risk of bleeding, compared with warfarin. One review of genotype-guided warfarin dosing assessed AF patients; no significant differences in stroke prevention were reported. Education about OACs, in patients with AF, could improve adherence. Pharmacist management of coagulation may be better than primary care management. Patients were more adherent to direct OACs than warfarin. Drug efficacy was highly valued by patients and most clinicians, followed by safety. No other factors consistently affected patients' choice of anticoagulant and adherence to treatment. Patients were more satisfied with direct OACs than warfarin.

CONCLUSIONS

For stroke prevention in AF, direct OACs seem to be more effective and safer than usual care, and apixaban (5 mg twice daily) had the best profile. For VTE, there was no strong evidence that direct OACs were better than usual care. Education and pharmacist management could improve coagulation control. Both clinicians and patients rated efficacy and safety as the most important factors in managing AF and VTE.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017084263-one deviation; efficacy and safety were from one review.

Can pharmacogenetics help patients under chronic treatment with coumarin anticoagulants?

Vitamin K antagonists are highly effective antithrombotic drugs. However, appropriate dosing is difficult to establish owing to its narrow therapeutic window as well as widespread inter- and intra-individual variability in dosage. Compared with dosing solely based on clinical information, pharmacogenetics can help improve the therapy with coumarins by decreasing the time to reach a stable dose and reducing the risk of bleeding. Most of the studies about genotyping of patients using vitamin K antagonists have focused on predicting the stable dose. Two genes have been shown to have the most influence on dosing: VKORC1 and CYP2C9. Furthermore, genotyping of more genes, such as CYP4F2 and APOE, is also being included in some dosing algorithms. The role of genotype beyond the initial dose-titration phase is less clear. Thus, a proven genetically determined risk of unstable dose or bleeding could help with the selection of patients who require more frequent monitoring of dose. On the other hand, patients who have a genetically determined stable dose could self-monitor their international normalized ratio (INR), making the therapy less expensive and more convenient.