People with cancer are at a high risk of developing a blood clot that forms in the body. This risk is even higher among the elderly and those with certain types of cancer such as gastrointestinal cancer. Even with the best existing treatments, people with cancer who have previously experienced blood clots are at a higher risk of developing another blood clot, compared to people without cancer.
Anticoagulants, also known as ‘blood thinners’, are medicines that treat or prevent blood clots from forming. However, these medicines also increase the risk of bleeding. The concerns of patients and physicians about this increased risk of bleeding is a common reason why many patients with cancer do not receive enough of the anticoagulant treatment or do not receive any treatment at all. Lack of tolerability and difficulty swallowing an oral medication, leading to poor adherence, are other causes that contribute to undertreatment. In addition, some treatments may negatively interact with anti-cancer drugs.
The purpose of this study is to learn more about how cancer patients with blood clots are treated in the real world, and about the outcomes of their treatment. The study has important public health benefits in that it will generate key evidence of the unmet need in these patients, which may be addressed with new policies, clinical guidelines, and therapies in development. This is expected to ultimately improve the quality of care and outcomes for cancer patients with blood clots.
Cancer-associated thrombosis (CAT), particularly venous thromboembolism (VTE), is a significant cause of morbidity and mortality in oncology patients. Whilst using antithrombotic agents for VTE treatment reduces the risk of VTE recurrence, the risk of haemorrhage is increased especially in the elderly and acutely ill patients. We propose to undertake a retrospective study using linked CPRD-Aurum and Hospital Episode Statistics (HES) datasets to understand the real-world treatment gap and the long- and short-term health outcomes in CAT patients. Specifically, we will assess rates of treatment discontinuation among newly diagnosed CAT patients and will compare the demographic, clinical characteristics, and clinical and economic outcomes of those who are treated for adequate duration (≥3 months) vs. undertreated (i.e., discontinued treatment before 3 months) or untreated.
The study’s main outcomes will be rates of major bleeds after the first observed thrombosis event. Secondary outcomes will include (i) rates of CAT recurrence after the first observed thrombosis, (ii) percentage of patients with evidence of re-treatment (for the treated and undertreated groups) and (iii) healthcare utilisation and costs to the National Health Service (NHS). Statistical comparisons among the above groups will be based on the Student t-test or Mann-Whitney test for continuous variables and chi-squared or Fisher’s exact test for categorical variables. Time-to-event analyses (time to major bleeds, CAT recurrence and re-treatment) will be performed using the Kaplan-Meier method and treatment groups will be compared using the log-rank test. A conventional alpha of 0.05 and a two-tailed level of significance will be used. All analyses will be performed using SAS ® or R statistical software.
This study will generate important evidence on the extent to which practice guidelines are being followed in real-world settings and may identify opportunities to improve the quality and outcomes of care in these patients across England and Wales.
The key outcomes are rates of treatment discontinuation over time of newly diagnosed CAT patients with antithrombotic agents and rates of major bleeds within specified intervals of the index thrombosis event. Secondary outcomes include rates of CAT re-occurrence and retreatment, as well as healthcare utilisation and costs.
Mihail Samnaliev - Chief Investigator - Stratevi
Mihail Samnaliev - Corresponding Applicant - Stratevi
Alexandra Ellis - Collaborator - Stratevi
David Wingfield - Collaborator - HAMMERSMITH & FULHAM PARTNERSHIP PCN
Mari Thomas - Collaborator - University College Hospital
Mihail Samnaliev - Collaborator - Stratevi
Roy Arguello - Collaborator - Stratevi
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;Patient Level Index of Multiple Deprivation