A “bundle of care” to improve anticoagulation control in patients receiving warfarin in Uganda and South Africa: Protocol for an Implementation Study (Preprint)

BACKGROUND The quality of warfarin anticoagulation among sub-Saharan African patients is sub-optimal. This is due to several factors including lack of standardized dosing algorithms; difficulty in providing timely INR results; lack of patient feedback on their experiences on treatment; lack of education on adherence and inadequate knowledge and training of healthcare workers. Low quality of warfarin anticoagulation, expressed as time in therapeutic range (TTR), is associated with higher adverse event rates including bleeding and thrombosis and poorer quality of life. OBJECTIVE This study aims to implement the ‘warfarin bundle’ -a package of interventions to improve the quality of anticoagulation and thereby clinical outcomes. METHODS Patients aged ≥ 18 years who are newly initiated on warfarin for venous thromboembolism (VTE), atrial fibrillation (AF) or valvular heart disease (VHD) will be enrolled and followed up for 3 months at clinics where the warfarin bundle is implemented. Retrospective review of clinical records of patients on warfarin treatment prior to implementation (controls) will be used for comparison. This study uses a mixed methods approach of implementation of patient and process -centred activities to improve the quality of anticoagulation. Patient-centred activities include use of dosing algorithms, adherence support and root cause analysis while process-centred activities include point of care INR testing, staff training and patient education and training. We will assess the impact of these interventions by comparing the TTR and safety outcomes across the two groups as well as cost-effectiveness and acceptability of the package. RESULTS We started recruitment in June 2021 and stopped in August 2022 having recruited 167 participants. We obtained ethics approval from the University of Cape Town Faculty of Health Sciences Human Research Ethics Committee, the Provincial Health Research Committees in South Africa, the Joint Clinical Research Centre Institutional Review Board, Kampala and the University of Liverpool Research Ethics Committee. As of February 2023, we are undertaking data cleaning and formal analysis. We expect to publish full results by December 2023. CONCLUSIONS We anticipate that the ‘bundle of care’ that includes a clinical algorithm to guide individualized dosing of warfarin, will improve INR control; and TTR of patients in Uganda and South Africa. We will use these findings to design a larger, multisite clinical trial in other sub-Saharan African countries.