With an aging population, more and more adults are diagnosed with an irregular heartbeat, a condition referred to as atrial fibrillation. This often-silent condition increases the risk of forming blood clots that may travel from the heart to the brain and lead to a stroke. Blood thinners (called anticoagulants) act on the blood and reduce the risk of forming clots and subsequent strokes, but they also increase the risk of bleeding. Much attention to date has focused on balancing the known risk of bleeding with the likely benefit of preventing a stroke. However, blood thinners may also cause kidney damage. Why this happens, and how important it is in clinical practice, is not very clear at this time. We will conduct a study that will explore the risk of kidney damage with the use of blood thinners in a large population of patients who are newly diagnosed with atrial fibrillation. Given the known adverse health effects of kidney damage, we believe our study may help in evaluating the overall harms and benefits of taking blood thinners among patients with atrial fibrillation.
The objective of this study is to examine the risk of acute kidney injury (AKI) with the use of oral anticoagulants in patients with atrial fibrillation (AFib). We will assemble a cohort of patients newly-diagnosed with AFib between 1998 and 2015 using the Clinical Practice Research Datalink (CPRD) with linkage to the Hospital Episode Statistics (HES), and the Office for National Statistics (ONS). Cohort entry will be defined by the first-ever diagnosis of AFib in the CPRD. Primary exposure will be defined in a time-dependent fashion as current use of vitamin K antagonists (VKA) or direct oral anticoagulants (DOACs), separately, and the reference group will be no current use of either. The primary outcome will be the first hospitalization with a diagnosis of AKI. Time-dependent Cox models will be used to estimate the hazard ratio for the association between current use of VKA or DOAC and AKI, compared with no use of either. This outcome will be assessed separately in patients with and without chronic kidney disease (CKD) at cohort entry. Secondary analyses will include duration-response analyses and a comparison of AKI risk with the initiation of VKA and DOACs.
Samy Suissa - Chief Investigator - Sir Mortimer B Davis Jewish General Hospital
Kristian Filion - Corresponding Applicant - McGill University
Adi Klil-Drori - Collaborator - Sir Mortimer B Davis Jewish General Hospital
Laurent Azoulay - Collaborator - McGill University
Rui Nie - Collaborator - McGill University
Sharon Nessim - Collaborator - McGill University
HES Admitted Patient Care;ONS Death Registration Data