Evaluating treatment patterns of venous thromboembolism patients in primary care

Study type
Protocol
Date of Approval
Study reference ID
20_000262
Lay Summary

Venous thromboembolism (VTE, which relates to blood clots in the legs and lungs) is an important cause of morbidity and mortality. It is estimated that over 10 million people worldwide are affected by this condition annually. Anticoagulant, blood-thinning drugs are available for the treatment of VTE i.e. apixaban, rivaroxaban, dabigatran, edoxaban and warfarin. There is limited contemporary data on how these drugs are being used in clinical practice to treat patients with VTE. Therefore, information available from the Clinical Practice Research Datalink (CPRD) will be used to describe the patterns of blood-thinning treatment used in primary care for patients with VTE. The study period will be 2013-2019. The use of different blood-thinning drugs, and the frequency of their use over time will be described in this study. This study will help to evaluate contemporary patterns of treatments among patients with VTE in the UK. This study will provide important information about what type of treatments are commonly used for treating patients with venous thromboembolism in routine clinical practice.

Technical Summary

Deep vein thrombosis (DVT) and pulmonary embolism (PE), collectively known as venous thromboembolism (VTE), comprise the third most frequent acute cardiovascular syndrome after myocardial infarction and stroke globally. Anticoagulation therapy is the mainstay of treatment for VTE patients. The use of oral vitamin K antagonists (VKAs), including warfarin, has historically been the commonest approach to anticoagulation treatment in VTE patients without cancer, but it is associated with several practical challenges, including numerous food and medication interactions, and the need for regular anticoagulation monitoring. The non-VKA oral anticoagulants (NOACs) have emerged as viable alternatives to VKA therapy in patients with VTE. Prospective, randomized clinical trials and real-world studies comparing NOACs to VKAs demonstrate comparable efficacy and the potential for improved safety, in terms of reductions in major bleeding such as intracranial haemorrhage (ICH). Up-to-date data to demonstrate how VKA or NOACs are currently being used to treat patients with VTE in routine clinical practice is, however, limited. The aim of the current study is to generate contemporary data describing trends over time in the use of oral anticoagulants. A retrospective cohort study using CPRD will be conducted to describe the treatment patterns and patient characteristics in VTE patients. The population of interest will include all incident VTE patients diagnosed between 1 January 2013 to 31 December 2019. The primary outcome of interest will be the frequency and type of oral anticoagulation prescribed following an incident VTE diagnosis. The study will be descriptive and therefore there is no primary exposure/comparator group. This study will generate evidence on changes in the use of oral anticoagulation over time, providing clinicians, patients and policy makers a population level view of current trends in VTE patient management, and facilitate comparison of these trends with established clinical guidelines.

Health Outcomes to be Measured

Primary Outcomes:
• Number and proportion of VTE patients receiving each treatment: apixaban, rivaroxaban, dabigatran, edoxaban and warfarin during the inclusion period (2013-2019), for the overall cohort of VTE patients, by calendar year and by VTE sub-groups (PE or DVT).

Secondary Outcomes:
Description of patient demographic and clinical characteristics according to:
• The cohort: for overall VTE cohort and by VTE sub-groups (PE, DVT) for the overall inclusion period
• Each treatment: apixaban, rivaroxaban, dabigatran, edoxaban and warfarin
- For the overall VTE cohort
- For each VTE sub-group (PE, and DVT)
• By calendar year for the inclusion period
- For the overall VTE cohort
- For each VTE sub-group (PE, and DVT)

Collaborators

Steven Lister - Chief Investigator - Bristol-Myers Squibb Pharmaceuticals Limited - UK ( BMS )
Robert Carroll - Corresponding Applicant - Bristol-Myers Squibb Pharmaceuticals Limited - UK ( BMS )
Kevin Pollock - Collaborator - Bristol-Myers Squibb Pharmaceuticals Limited - UK ( BMS )
Lianne More - Collaborator - Pfizer Ltd - UK
Raza Alikhan - Collaborator - University Hospital of Wales