Title: HIDDEN: Hospice Inpatient Deep vein thrombosis Detection study
Funder: Department of Health and Social Care

Abstract: Background Venous thromboembolism (VTE) affects an estimated 4-20% of patients with cancer during the course of their illness; the true frequency is unknown as VTE can be asymptomatic. There are UK guidelines for the prevention of VTE in cancer patients admitted to hospital but we do not know whether they should be applied to advanced cancer patients admitted to specialist palliative care units (SPCU) such as hospices. There is little evidence regarding the prevalence and incidence of VTE in these patients or whether there are symptom control, quality of life and survival benefits of VTE prevention and treatment, although we do know that patients with advanced cancer have a higher risk of bleeding with anticoagulant treatment of VTE than those with early stage disease. Establishing the true prevalence of DVT and associations with relevant symptoms and outcomes would help to inform the clinical management of patients with advanced cancer admitted to SPCUs. Aims and Objectives Aims The primary aim of the HIDDen study is to establish the clinically significant prevalence of proximal lower limb deep vein thrombosis (DVT) in cancer patients admitted to a SPCU. Objectives Primary: To determine the prevalence of proximal lower limb DVT in cancer patients admitted to SPCUs. Secondary: In patients with cancer and non-malignant conditions admitted to a SPCU to: assess longitudinally the weekly incidence of developing a proximal lower limb DVT during admission; determine the clinical signs and symptoms associated with proximal lower limb DVT including signs and symptoms, acute deterioration or sudden death, that could be attributed clinically to pulmonary emboli; describe the clinical characteristics of patients with and without proximal lower limb DVT; compare the prevalence and weekly incidence of proximal lower limb DVT between those with a non-malignant condition and those with cancer; determine the sensitivity and specificity of a clinical risk score for DVT (Well s score). Study Design The proposed HIDDen study is a prospective, multicentre longitudinal observational study. Consecutive admissions to SPCUs in England (one site), Northern Ireland (three sites) and Wales (one site) will be invited to participate until 217 cancer patients are recruited. Cancer patients form approximately 80% of the hospice in-patient population and so we anticipate approximately 270 participants in total. As patients who are unable to consent for themselves are an important subgroup where we currently do not know the best way to manage their risk of VTE, and who may have a different prognosis from those with capacity, we will seek agreement from an appropriate consultee to include such patients in the study. Participants will be scanned for proximal lower limb DVT using Doppler ultrasound on admission and then weekly for the duration of their stay. Weekly assessments will also be undertaken to assess any associated symptoms and clinical signs which could be due to VTE. Descriptive statistics will be used to describe outcomes, correlation between clinical findings and Doppler results. Multivariate analyses will be used to identify baseline variables with an independent contribution for predicting the development of DVT/symptoms. The sensitivity and specificity of the Well s score as a clinical score for the diagnosis of DVT will also be calculated. Potential Benefits to Patients and the NHS The results of this study will inform clinical practice regarding VTE prevention in SPCUs. A 15-25% DVT detection rate in admissions to SPCUs, associated with clinically relevant symptoms and complications, would be evidence to support routine VTE assessment of advanced cancer patients on SPCU admission. In addition, the data arising from this study may also inform clinical decisions about management of asymptomatic DVTs.

Lay abstract: Up to one in five cancer patients will develop blood clots in their veins known as deep vein thrombosis (DVT). A clot may break off from the DVT and travel to the lungs; known as a pulmonary embolism (PE). We do not know the true number of DVTS and PE as they may not cause symptoms. Neither do we know whether apparently &ldquo;silent&rdquo; DVTs, if untreated, go away by themselves, or go on to cause serious problems like swollen, painful legs (DVT), or chest pain, breathlessness, collapse or death (PE). There are national treatment recommendations to prevent DVT in cancer patients admitted to hospital. However, we do not know whether these should apply to patients with advanced cancer admitted to specialist palliative care units (SPCU) such as hospices, as treatment may not alter how long patients have to live or improve symptoms and quality of life. We do not know if good effects outweigh side-effects of treatment (e.g. bleeding) in these patients. The aim of the HIDDen study is to find out how many cancer patients admitted to hospice units have a DVT. An ultrasound scanner (a safe simple scan which uses sound waves like the scans used in pregnant women to see the baby in the womb), at the hospice bedside, will be used to scan patients legs to test whether they have a DVT. Symptoms will be noted, and patients re-scanned a week later. Consecutive admissions to hospices in England (one site), Northern Ireland (three sites) and Wales (one site) will be recruited until at least 217 cancer patients have been scanned. This study will tell us how many cancer patients admitted to hospice units have DVTs and whether these cause problems. We will then understand better how we should treat people with advanced cancer.

Research activity codes: 4.4 POPULATION SCREENING
Health categories: BLOOD;CANCER AND NEOPLASMS