Clinical and Economic Burden of Bleeding Events in Patients in the UK With Non-valvular Atrial Fibrillation Treated With Vitamin k Antagonists

Inclusion criteria

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For the CPRD-HES cohort, patients will be included if they meet these criteria:

• Have CPRD data linked to HES
• Have an AF diagnosis (based on Read codes from CPRD or ICD-10 codes from HES) and have been treated with VKA during the study period

-≥18 years old at index date

• CPRD acceptability quality criteria are present.

For the CPRD cohort, patients will be included if they meet the following criteria:

• Have an Atrial Fibrillation (AF) diagnosis (based on Read codes from CPRD) and have been treated with VKAs during the study period
• ≥18 years old at index date
• CPRD acceptability quality criteria are present.

Exclusion criteria

For the two cohorts of interest, patients will be excluded if they meet the following criteria:

• Fewer than 12 months of computerised data available prior to the index date (in order to provide a minimum amount of computerised history and to avoid issues associated with updating records when a patient joins a practice). The date of start of computerized records will be the latter of the patient's date of registration with the practice or the practice's Up-to-Standard (UTS) date (when the practice is deemed to be contributing data of adequate quality)
• The practice is not UTS, or the patient is deemed "unacceptable" according to CPRD's quality criteria
• There is evidence of valvular disease, repair, or replacement before (ie, up to 12 months prior to the index date) or during the study period
• There are records of Novel anticoagulant (NOAC)