Adherence of Apixaban and Warfarin in Patients With Arterial Fibrillation in Real-world Setting in Sweden

This will be a retrospective cohort study using national register linkage data (including prescription, inpatient, mortality, and socioeconomic data). The study period will be from May 29, 2013 to June 30, 2015. Patients will be followed from the start of treatment (index date) until their death, exiting the database, or until the end of the study period (June 30, 2015).

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Key information

Conditions

Anticoagulation

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

For the AF cohort

Patients that have ≥1 AF diagnosis registered in the patient register
Apixaban subcohort 1

Patients eligible for the AF cohort
Patients that had a first prescription for apixaban during the identification period without previous prescriptions for NOACs or warfarin during the preceding 12 months
Warfarin subcohort 1

Patients eligible for the AF cohort
Patients that had a first prescription for warfarin during the identification period without previous prescriptions for NOACs or warfarin during the preceding 12 months
Apixaban subcohort 2

Patients eligible for the AF cohort
Patients that had a first prescription for apixaban during

Exclusion criteria

For the AF cohort:

Patients with valvular AF will be excluded (see definition Appendix 1)
Warfarin subcohort 1:

Patients will be excluded from this sub-cohort if they had at least one prescription for warfarin or NOACs during the 12-month period preceding the first prescription for warfarin during the identification period, ie, the index date

Treatment and study plan

Primary outcomes

Compare adherence among Atrial Fibrillation (AF) patients initiating treatment with apixaban (without previous warfarin or novel anticoagulant (NOAC) use) compared with those initiating treatment with warfarin (without previous warfarin or NOAC use)

Time frame: approximately 6 to 12 months

Adherence: Adherence will be defined including missing doses and treatment discontinuation using the following approaches:

"Drug at disposal" approach: Based on information on prescribed dosing (mg/day) and information on filled prescriptions (mg expensed from the pharmacy); it is possible to calculate for how long a period the drug will last for that specific patient. Adherence is then defined using the Medication Possession Ratio (MPR) calculated as the ratio of number of days of treatment supply divided by the total length of follow-up time, and converted to a percentage (in the graph below illustrated as the sum of the grey horizontal bars divided by the length of follow-up, ie, time between index date and end of follow-up). The MPR will be computed as a continuous and binary variable (MPR>80%, ie, high vs low adherence)
Compare persistence among AF patients initiating treatment with apixaban (without previous warfarin or NOAC use) compared with those initiating treatment with warfarin (without previous warfarin or NOAC use)

Time frame: approximately 6 to 12 months
Persistence: Persistence will be defined as treatment discontinuation and will be measured by estimating the following:
- Time to discontinuation: Date of therapy cessation is not possible to determine with certainty due to the nature of registry data. In order to be able to estimate the time of discontinuation, patients will be considered on treatment for the full time between two purchases as long as they have at least one refill in a six month period. If there is no new purchase within six months the patient is considered to have terminated treatment at a date corresponding to how long the last prescription will last (in the graph below illustrated as the time between index date and the end of the "last" horizontal bar).
- Cumulative incidence of persistent patients still on index treatment at the every 3- month interval after index date (treatment initiation)

Secondary outcomes

Describe and compare patient characteristics (demographics) among AF patients through questionnaire

Time frame: approximately 6 to 12 months
Describe and compare patient characteristics (eg, demographics and clinical) among AF patients who:
- Initiate apixaban without previous anticoagulant treatment (warfarin or NOAC use)
- Initiate apixaban with previous war
Demographic parameters : Age-groups, Sex, Socioeconomic variables (e.g. education, disposable income)
Describe and compare patient characteristics (clinical) among AF patients through questionnaire

Time frame: approximately 6 to 12 months
Describe and compare patient characteristics (eg, demographics and clinical) among AF patients who:
- Initiate apixaban without previous anticoagulant treatment (warfarin or NOAC use)
- Initiate apixaban with previous war
Clinical Characteristics: History of stroke/TIA/systemic, embolism, Diabetes, Hypertension, Heart failure, Vascular disease, Intracranial bleeding, Any bleeding, Kidney disease, Liver disease, Dementia, Valvular AF, Ischemic stroke, Unspecified stroke, TIA, Systemic embolism, Coronary disease, End Stage Renal Disease

Sponsors and collaborators

Lead sponsor

Bristol-Myers Squibb

Industry

Registry information

Official study title

Adherence of Apixaban and Warfarin in Patients With Atrial Fibrillation in Real-world Setting in Sweden

Important dates

Study start: 2014
Primary completion: 2016
Study completion: 2016
First posted: Jul 9, 2015
Registry last updated: May 18, 2016

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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