What do we want to know?
Anticoagulation drugs are used to prevent and treat irregular heartbeat (atrial fibrillation, AF), and clotting of blood in veins (venous thromboembolism, VTE). Until recently, warfarin was the only available drug to manage or prevent these conditions. Recently, novel oral anticoagulants (NOACs) have become available for prescription. To bring together current understanding about these treatments, we sought to address broad research questions: What evidence syntheses have been conducted to address the efficacy and safety of UK-approved oral anticoagulant therapy with respect to warfarin, novel oral anticoagulants, genotyping (i.e. using genetic information to guide treatment) and self-monitoring? What evidence syntheses have been conducted to understand patient and clinician experiences of UK-approved oral anticoagulant therapy with respect to lifestyle impacts, compliance and adherence, beliefs about use and issues of blood monitoring?
Who wants to know?
This review was commissioned by the Department of Health and Social Care and the NHS Social Care Medicines, Diagnostics and Personalised Medicines Unit. Findings will be of interest to local commissioners, health practitioners and managers, patients, members of the public and researchers.
What did we find?
Efficacy and safety of NOACs
- Findings from low-quality evidence suggests that NOACs are better than warfarin for the prevention of AF-related stroke (when the blood supply to part of the brain is cut off) and in terms of safety (e.g. from bleeding, the main effect of overdose which can lead to death).
- There is no strong evidence supporting the use of NOACs for primary prevention, acute treatment and secondary prevention of VTE.
- Evidence of genotyping concerns multiple conditions and is not specific to patients with AF or VTE, suggesting a need for rigorous evaluations of pharmacogenetics in these populations.
Interventions to support optimal use of oral anticoagulants
- Low- and moderate-quality evidence suggests that education with and without decision aids, self-management and self-monitoring may improve consistent INR and TTR blood values, but findings are not consistent.
- Some pharmacy-based interventions may help patients to achieve optimal levels of anticoagulation compared with routine medical care.
Patient and clinician decision-making
- Clinician and patient decision-making is informed by drug efficacy and safety, particularly when starting, changing or continuing oral anticoagulant medication.
- Other factors may influence decisions, including patients’ knowledge, experience, changes in cognition and memory due to the condition itself, and patient characteristics such as age, gender, lifestyle, employment status and support needs. Patient-clinician communication and perceptions about who bears the responsibility for decision-making are also important.
What are the conclusions?
Whilst some evidence suggests that NOACs are more effective than warfarin among AF populations, there was no strong evidence that NOACs should replace warfarin in the prevention of VTE. It seems unlikely that NOACs will be suitable for all patients with AF, therefore further research is needed to identify which drugs are better for whom, and in what circumstances. The evidence suggests that self- and pharmacy-based management interventions to achieve appropriate blood anticoagulant levels are promising, but there are too few studies available to reach reliable conclusions. Where efficacy and safety of specific oral anticoagulation therapies have been established, the next priority should be to consider which factors matter to patients and clinicians. This is because a wide range of other factors may also influence treatment and maintenance decisions. This knowledge could help clinicians to determine the level of support and information to provide to patients, including communication of risks, benefits and preferences.
How did we get these results?
A rapid systematic overview of reviews of oral anticoagulant therapy and patient/clinician experience was undertaken. We searched a broad range of sources, then screened with specific inclusion and exclusions criteria to identify studies. From these, we undertook data extraction and synthesis using previously developed tools. Each stage undertaken by two or more researchers. We identified four reviews examining efficacy and safety; ten reviews examining genotyping; six reviews on the management of appropriate levels of anticoagulation; and eight reviews of patient and provider perspectives of oral anticoagulant therapy. Each set of reviews was tabulated and narratively synthesised.
These reports should be cited as:
Brunton G, Richardson M, Stokes G, Blanchard L, Burchett H, Khatwa M, Khouja C, Walker R, Wright K, Sowden A, Thomas J (2018) The effective, safe and appropriate use of anticoagulation medicines: A systematic overview of reviews. London: EPPI-Centre, Social Science Research Unit, UCL Institute of Education, University College London.