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 also carries an inherent risk of causing or exacerbating bleeding. This has important clinical implications as well as costs to society.
We propose to estimate the costs to the UK National Health Service (NHS) that may be attributed to bleeding following atrial fibrillation (AF). We will also investigate whether there is a greater risk of particular clinical outcomes among those who have had a bleeding event, including the probability of discontinuing OAC treatment and the chances of experiencing further bleeding, having a stroke or heart attack or dying.
We aim to provide information that will help doctors and policy makers to better understand the implications of treatment with different OAC therapies that are associated with greater or lesser risk of bleeding for AF patients.
Oral anticoagulant (OAC) therapy is used to reduce the risk of stroke in non-valvular atrial fibrillation (NVAF) patients but carries a risk of causing or exacerbating bleeding.
The objective of the study is to estimate the 3-year healthcare costs attributable to a GI bleed in AF patients by comparing total costs among individuals with AF who experienced GI bleeding with a matched control group of AF patients who did not suffer GI bleeding. The primary outcome is total healthcare costs (costs associated with GP consultations, inpatient stays, outpatient visits and prescriptions). The secondary outcomes are treatment discontinuation, subsequent bleeds, stroke/TIA and death.
Controls will be selected using propensity score matching. Logistic regression of the risk of GI bleeding among cases and potential control subjects will be modelled as a function of a set of demographics, stroke risk factors, bleeding risk factors, year of first eligibility in data, and other covariates. Nearest neighbour matching on the propensity score with replacement will be carried out to match each bleeding case with up to 4 controls.
For both cases and controls, total costs will be estimated by encounter type. Standard unit cost methodology will be applied to obtain costs for primary care and outpatient hospital encounters. For inpatient stays, costs will be estimated based on the clinical complexity of the patient using NHS Healthcare Resource Groups (HRGs). For prescription drugs, costs will be applied using the mean cost of drugs within the applicable BNF subchapter.
A difference-in-differences approach will be taken to estimate the costs attributable to GI bleeds. We will estimate the change from baseline year to incidence year in total healthcare costs for patients who have experienced a GI bleed following AF (cases) net of the change over time in costs experienced by AF patients who did not experience a GI bleed during the period (controls).
The primary outcome in this project will be the total healthcare costs attributable to GI bleeding, which will include costs associated with GP consultations, inpatient stays, outpatient visits and prescriptions.
The secondary outcomes in the project will be treatment discontinuation, subsequent bleeds, stroke/TIA and death.
Sreeram Ramagopalan - Chief Investigator - London School Of Economics & Political Science
Cormac Sammon - Corresponding Applicant - PHMR Associates Limited ( UK )
Mihail Samnaliev - Collaborator - Maverex Ltd
Sharada Weir - Collaborator - Maverex Ltd
Tzu-Chun Kuo - Collaborator - PHMR Associates Limited ( UK )
HES Admitted Patient Care;HES Outpatient;Patient Level Index of Multiple Deprivation;Patient Level Townsend Score