Treatment of venous thromboembolism in cancer patients, Venous Thromboembolism, Cancer

Trial Purpose

This is an observational study in which patient data from the past on venous thromboembolism (VTE) in people with cancer is studied. In observational studies, only observations are made without specified advice or interventions.
People with VTE have problems due to the formation of blood clots in the veins. Blood clots can reduce the flow of blood to vital organs such as the lungs, which can lead to their damage. VTE can also be “recurrent”. This means that the blood clots have returned after treatment. People who have cancer are more likely to develop VTE, recurrent clots, and bleeding on blood thinning treatments.
To prevent the formation of new or recurrent clots in people with cancer, a newer type of blood thinner is available, called direct-acting oral anticoagulant (DOAC). Rivaroxaban and apixaban are the most used DOACs in the US. They work by blocking a certain step in the blood clotting process, the activation of a protein called Factor X.
Previous studies show that DOACs may reduce clot risk compared to other available treatments but may potentially lead to more frequent bleeding. Studies looking at these points in direct comparison of rivaroxaban and apixaban a currently missing.
Therefore, this study will collect real-world data from the US to learn how well rivaroxaban works and how safe it is compared to apixaban in people with cancer and VTE who are at low risk for bleeding.

To do this, researchers will look at the proportion of patients that will develop:
•    recurrent blood clots in the veins after treatment
•    bleeding in a critical organ
•    bleeding that requires a hospital stay
within 3 and 6 months after participants had a VTE that was treated with rivaroxaban or apixaban.

De-identified data collected will cover 12 months before and at maximum 6 months after this VTE. They will come from US electronic health records and will cover the years 2012 to 2020.
No visits or tests are required as part of this study.

- Be ≥18 years of age at the time of anticoagulation initiation.
- Have active cancer defined as cancer being actively treated, diagnosed within 6-months prior of the index CAT or associated with metastatic disease (regardless of time from initial cancer diagnosis)
- Admitted to the hospital, emergency department or observation unit for acute Deep vein thrombosis (DVT) and/or Pulmonary embolism (PE)
- Started on a therapeutic VTE dose of rivaroxaban or apixaban within 7 days of the qualifying VTE event and treated with a therapeutic VTE dose of rivaroxaban or apixaban as their first anticoagulant on day 7 post-acute CAT event diagnosis (index date) to increase the probability of accurately classifying patients’ intended outpatient anticoagulant for CAT treatment, and that, patients are compared at the same point from diagnosis.
-  Have been active in the data set for at least 12-months prior to the index event (based on the “First Month Active” field) and had at least one provider visit in the 12-months prior to the acute VTE event (baseline period).

- Oesophageal, gastric, unresected colorectal, bladder, central nervous system cancers (except brain) and leukaemia
- Evidence of atrial fibrillation, recent hip/knee replacement (within 35 days of index VTE), ongoing VTE treatment, valvular heart disease defined as any rheumatic heart disease, mitral stenosis, or mitral valve repair/replacement.  
- Pregnancy.
- Initiation of non-therapeutic VTE doses of rivaroxaban or apixaban.
- Evidence of anticoagulation use written prescription or patient self-report during the 12-months prior to the qualifying CAT event per.