A blood clot may form in any vein in the body. Blood clots most commonly occur in the veins in the leg and may break off and travel to the lungs, which can be fatal. Treatment of blood clots is with 'blood thinning' medication. The most serious side effect of blood thinning medication is that it causes bleeding. In the past it has been necessary to monitor blood thinning treatment with regular blood tests. New blood thinning tablets have been developed which have a lower risk of bleeding and do not require regular monitoring. Current National and International Guidelines recommend that all patients who have suffered an episode of blood clot in the legs or lung should be assessed and considered for long term blood thinning medication treatment to reduce the risk of suffering a recurrent blood clot. Real world evidence, utilising the Clinical Practice Research Datalink, Hospital Episode Statistics and Office for National Statistics dataset, can provide additional insight on the role of long term blood thinning medication in patients suffering a blood clot. This research will help inform doctors on the safety and effectiveness of blood thinning medication and thereby help improve the clinical care of VTE patients.
VTE is characterised by the forming of blood clots in blood vessels, and includes deep vein thrombosis (DVT) and pulmonary embolism (PE). In addition to a high case-fatality rate, recurrence is common. Treatment for VTE focuses on inhibiting the function of clotting factors and breaking up existing clots. Traditional treatment involves vitamin-K-antagonists (VKA), most commonly warfarin. However, novel oral anticoagulants (NOACs) are likely to replace warfarin given the evidence of non-inferiority in randomised trials, and their association with reductions in the risk of bleeding. The current study aims to investigate the use and effectiveness of anticoagulants in VTE patients in England. A retrospective cohort study design will be utilised. Patient characteristics, treatment patterns and the risk of clinical events of interest will be compared between patients initiating different OAC treatments. The risk of clinical events of interest will be investigated by treatment class using Kaplan-Meier and Cox-regression analyses. The frequency of all-cause and VTE-related HCRU will be described and rates of use by person-time will be reported. Multivariable modelling will be used to estimate the association of OAC treatment with the rate of HCRU, while controlling for possible confounding factors. Propensity score matching will be used to limit bias/confounding.
Treatment patterns (including duration/ discontinuation, augmentation and persistence); Recurrent venous thromboembolism (VTE); Major and clinically relevant non-major bleeding; All-cause mortality; Hospitalisations; Hospital length of stay (LOS); Number of GP visits.
Dimitra Lambrelli - Chief Investigator - Evidera, Inc
Robert Carroll - Corresponding Applicant - Bristol-Myers Squibb Pharmaceuticals Limited - UK ( BMS )
Anna Schultze - Collaborator - Evidera, Inc
Beth Nordstrom - Collaborator - Evidera, Inc
Raza Alikhan - Collaborator - University Hospital of Wales
Sreeram Ramagopalan - Collaborator - London School Of Economics & Political Science
HES Admitted Patient Care;ONS Death Registration Data;Patient Level Index of Multiple Deprivation