Non-valvular atrial fibrillation (NVAF) is an irregular heart beat in individuals who do not have artificial heart valves or a heart valve problem. Patients with NVAF are five times more likely to have a stroke compared to patients who do not have the condition.
Oral anticoagulant (OAC) therapy is an effective and guideline-directed approach used to reduce the risk of stroke in NVAF patients. However, OAC therapy remains underused in high-risk patients with atrial fibrillation, thus increasing the risk of illness and death.
There may be a number of factors that affect a patients likelihood to be prescribed OACs, such as increased risk of bleeding. A thorough understanding of the clinical characteristics is needed to understand whether there are certain patient groups who may go unnecessarily undertreated.
This study will use a large patient database in order to investigate the differences in clinical characteristics between OAC-treated and OAC-untreated NVAF patients. By identifying the groups of patients who are undertreated, this study will be able to aid decisions about the best choice of treatment for this group, thus reducing the risk of stroke.
Objectives
To compare the clinical characteristics between patients treated or untreated with oral anticoagulants (OACs) who are newly diagnosed with non-valvular atrial fibrillation (NVAF).
Methods
This will be a descriptive and exploratory population-based case-control study in patients who are newly diagnosed with NVAF. Patients with an incident NVAF will be identified from the Clinical Practice Research Datalink (CPRD) and Hospital Episode Statistics (HES) for a 5-year period between 2013 to 2017. Prescriptions with relevant OAC drug codes will be identified to classify individuals as OAC-treated (controls), and those remaining (i.e. without an OAC prescription) will be classed as OAC-untreated (cases).
Data analysis
Appropriate descriptive statistics will be used to summarise relevant clinical characteristics (Section N). These will be categorised to reflect OAC treatment status. Subgroup analysis will be performed stratified by calendar year, in those with paroxysmal NVAF and in dementia patients
Univariable and multivariable logistic regression models will be used to estimate odds ratios comparing the odds of each event between cases and controls.
Sensitivity analysis will include different pre-index follow-up time.
Bleeding history/predisposition
Liver disease
Prescription of drugs predisposing to bleeding
Modified HAS-BLED score
Stroke/transient ischemic attack
Systemic thromboembolism
Congestive heart failure
Vascular diseases
Hypertension
Diabetes
CHAD2 score
CHA2DS2-VASc score
BMI
Weight
Cancer status
Falls
Deprivation (IMD)
Paroxysmal NVAF
Dementia
Sreeram Ramagopalan - Chief Investigator - London School Of Economics & Political Science
Cormac Sammon - Corresponding Applicant - PHMR Associates Limited ( UK )
Elaine Stamp - Collaborator - PHMR Associates Limited ( UK )
Megan Besford - Collaborator - PHMR Associates Limited ( UK )
HES Admitted Patient Care;Patient Level Index of Multiple Deprivation