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Atrial Fibrillation and FlutterPhase 4DANWARDNCT03862859

The Danish Warfarin-Dialysis Study - Safety and Efficacy of Warfarin in Patients With Atrial Fibrillation on Dialysis

A Phase 4 study testing Warfarin in people with Atrial Fibrillation and Flutter and Stroke, run by Nicholas Carlson at 13 sites in Denmark.

Recruiting

Looking for participants now. Contact the study team or a site below to ask about taking part.

Sites and contacts
Official record
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Trial summary

The study aims to evaluate the appropriateness of initiating oral anticoagulation for stroke risk reduction in dialysis populations with atrial fibrillation. Specifically, the study will assess the overall safety, tolerability, and efficacy of initiating treatment with Warfarin in patients with end-stage renal disease… Read more about this study

Who is it for?
Ages 18 years and older
What is being tested?
Warfarin
Could I receive a placebo?
No, everyone receives an active treatment
How many people
718 participants
Where
13 sitesDenmark
Study dates
9 Oct 2019to Jan 2027
Phase
Phase 4
Are there results?
Not yet: the study is under way

Key requirements

Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.

  • Ages 18 years and older
  • All sexes
  • No healthy volunteers
  • Adult, Older adult

Who may be able to join

  • Patients ≥18 years on chronic dialysis due to end-stage renal disease
  • Non-valvular paroxysmal, persistent, or permanent atrial fibrillation OR non-treated (for >2 months) prevalent paroxysmal, persistent or permanent atrial fibrillation as documented by an electrocardiogram or an episode of ≥30 seconds on Holter monitor, or episodes ≥ 6 minutes on event recorders or any other recording device.
  • Competence to understand the study rationale, including potential risks and benefits associated with treatment, necessary for written informed consent.

Who cannot join

  • CHA2DS2-VASc Score ≤1
  • Other indications for oral anticoagulation treatment (pulmonary embolism < 6 months, deep vein thrombosis <3 months, mechanical heart valve prosthesis) irrespective of whether treatment is implemented
  • Ongoing dual antiplatelet treatment
  • Malignancy (with exception of non-melanoma skin cancer) with recent < 1 year, ongoing, or planned curative, or palliative chemo- , radiation-, and/or scheduled surgical therapy
  • Endoscopy with gastrointestinal ulcer <1 month
  • Esophageal varices
Show all 24Show fewer
  • Autoimmune og genetic coagulation disorders
  • Congenital alactasia, Lapp Lactase deficiency or glucose-galactose malabsorption
  • Pending spinal tap
  • Cerebrovascular malformations
  • Arterial aneurysms
  • Ulcers or wounds (Wagner grad >1)
  • Bacterial endocarditis < 3 months
  • Active bleeding contraindicating anticoagulation
  • Any non-elective and/or non-ambulant surgery <7 days
  • Cerebral hemorrhage <4 weeks
  • Thrombocytopenia (platelet count <100 × 109/L) <30 days.
  • Severe liver insufficiency (spontaneous international normalized ratio >1.5) <30 days.
  • Known intolerance to warfarin
  • Use of hypericum perforatum / St. John's Wort
  • Uncontrolled hypertension (repeat blood pressure >180/110 mmhg) < 30 days
  • Uncontrolled hyperthyroidism (thyroid-stimulating hormone <0.1μIU/mL) <30 days
  • Pregnancy or lactation
  • Participation in other ongoing intervention trials adjudged to influence study outcomes

Trial locations and contacts

13 sites in 1 country. Contact the study team or a site near you to ask about taking part.

Nicholas Carlson, MD PhD Ass. Prof contact

+45 35455927

nicholas.carlson.01@regionh.dk

Ellen LF Ballegaard, MD PhD contact

ellen.linnea.freese.ballegaard@regionh.dk

13 sites in 1 country

Denmark13 sites, 13 recruiting

  • Aalborg University Hosptial

    Aalborg, 9100

    Jesper M Rantanen, MD PhD, jemr@rn.dk

    Recruiting

  • Aarhus University Hospital

    Aarhus, 8200

    Christian D Peters, MD PhD, chipte@rm.dk

    Recruiting

  • Department of Nephrology, Copenhagen University Hospital Rigshospitalet

    Copenhagen, 2100

    Nicholas Carlson, MD PhD, +45 35455927, nicholas.carlson.01@regionh.dk

    Nicholas Carlson, MD PhD

    Recruiting

  • Esbjerg and Grindsted Hospital

    Esbjerg, 6700

    Alice S Nielsen, MD, alice.skovhede.nielsen@rsyd.dk

    Johanne K Breinholt, MD, johanne.kodal.breinholt@rsyd.dk

    Recruiting

  • Department of Nephrology, Herlev Hospital

    Herlev, Herlev, 2730

    Kristine Lindhard Rasmussen, MD, kristine.lindhard.rasmussen@regionh.dk

    Kristine Lindhard Rasmussen, MD

    Recruiting

  • Department of nephrology, Nordsjaellands Hospital

    Hillerød, Hillerød, 3400

    Marianne Bertelsen, MD, marianne.camilla.bertelsen@regionh.dk

    Marianne Bertelsen, MD

    Recruiting

  • Holbaek Hospital

    Holbæk, 4300

    Morten Lindhardt, MD PhD, moli@regionsjaelland.dk

    Recruiting

  • Holstebro Hospital

    Holstebro, 7500

    Frank H Mose, MD PhD, frank.holden.christensen@vest.rm.dk

    Recruiting

  • Lillebælt Hospital

    Kolding

    Donata Cibulskyte-Ninkovic, MD, donata.cibulskyte-ninkovic@rsyd.dk

    Recruiting

  • Bornholms Hospital

    Rønne, 3700

    Finn T Nielsen, MD, finnthomsen.nielsen@regionh.dk

    Recruiting

  • Zealand University Hospital

    Roskilde, 4000

    Rikke Borg, MD PhD, rbor@regionsjaelland.dk

    Lene Boesby, MD PhD

    Recruiting

  • Hospital Sønderjylland

    Sønderborg, 6400

    Jan D Kampmann, MD, jdk@rsyd.dk

    Recruiting

  • Viborg Regional Hospital

    Viborg, 8800

    Ida Tietze, MD PhD, ida@tietze.dk

    Recruiting

Other trials in Denmark

About this study

Official title: The Danish Warfarin-Dialysis Study: Safety and Efficacy of Warfarin in Patients With Atrial Fibrillation on Dialysis - A Nationwide Parallel-group Open Randomized Clinical Trial

The study aims to evaluate the appropriateness of initiating oral anticoagulation for stroke risk reduction in dialysis populations with atrial fibrillation. Specifically, the study will assess the overall safety, tolerability, and efficacy of initiating treatment with Warfarin in patients with end-stage renal disease on dialysis and atrial fibrillation.

Read the detailed description

Data pertaining to the tolerability, safety, and benefit of initiating anticoagulation for stroke risk reduction in patients with end-stage renal disease and atrial fibrillation remains conflicting and insufficient. Patients on dialysis continue to be routinely excluded from randomized controlled trials, and evidence from observational studies is plausibly biased. The main objective of the following parallel-group open randomized clinical trial presents a nationwide study aimed at investigating the benefit, tolerability, and safety of initiating warfarin versus no treatment in patients with atrial fibrillation on dialysis. The anticipated results from this project will provide conclusive evidence as to the appropriateness of initiating oral anticoagulation for stroke risk reduction in dialysis populations with atrial fibrillation with direct effects on clinical management and international guidelines pertaining to these patients.

The study is planned as a multicentre, randomized, open label, parallel group trial with planned inclusion of a total of 718 patients (359 patients per arm). Dialysis-treated patients with end-stage renal disease with paroxysmal, persistent, or permanent atrial fibrillation will be enrolled and randomized to either treatment with warfarin or no treatment. Randomization with be attained using a 1:1 allocation as per a computer-generated randomization schedule stratified by gender, age by decade, and center using permuted blocks of random sizes. Study participants will be allocated to treatment in accordance with the randomization for the full duration of the trial i.e. at a minimum one year following randomization, and followed with regular monitoring for the the primary efficacy outcome of ischemic stroke or death due to ischemic or unspecified stroke and the primary safety outcome of major bleeding defined in accordance with the International Society on Thrombosis and Hemostasis definition.

Being tested
Warfarin
Medical subject headings
Atrial Fibrillation, Stroke, Kidney Failure, Chronic

What participants receive

What participants receive. In a randomised study each person is assigned to one group by chance.

  • WarfarinDrug

    Also called Coumadin, Marevan, Jantoven

    Dose adjusted Warfarin targeting an international normalized ratio of 2-3.

Study groups in NCT03862859
Study groupRoleWhat they receive
Treatment with WarfarinActive comparatorWarfarin with dosing targeting an international normalized ratio of 2-3.
Receives: Drug: Warfarin
No treatmentNo interventionNo treatment

What is being measured

The primary outcome is the main question the study is designed to answer.

  1. Primary efficacy outcome - Number of participants with transient ischemic attack, fatal and non-fatal ischaemic or unspecific stroke

    Any transient ischemic attack, fatal and non-fatal ischaemic or unspecific stroke or death attributable to either ischemic or undefined stroke

    Measured: From randomization to end of observation - up to 4 years

  2. Primary safety outcome - Number of participants with fatal or non-fatal major bleeding

    Any major bleeding as defined in accordance with the International Society on Thrombosis and Hemostasis definition pertaining to major bleeding in non-surgical patients

    Measured: From randomization to end of observation - up to 4 years

Secondary outcomes (7)

  1. Number of participants with ischemic or unspecified stroke

    Any non-fatal or fatal ischemic stroke or unspecified stroke event

    Measured: From time of randomization to end of observation - up to 4 years

  2. Number of participants with ischemic stroke

    Any non-fatal or fatal ischemic stroke event

    Measured: From time of randomization to end of observation - up to 4 years

  3. Number of participants with hemorrhagic stroke

    Any non-fatal or fatal hemorrhagic stroke event

    Measured: From time of randomization to end of observation - up to 4 years

  4. Number of participants with ischemic or hemorrhagic stroke

    Any non-fatal or fatal ischemic or hemorrhagic stroke event

    Measured: From time of randomization to end of observation - up to 4 years

  5. Number of deaths

    All-cause mortality

    Measured: From time of randomization to end of observation - up to 4 years

  6. The combination of any non-fatal stroke and all-cause mortality

    Number of participants with either non-fatal ischemic or hemorrhagic stroke of death due to any cause

    Measured: From time of randomization to end of observation - up to 4 years

  7. The combination of any non-fatal stroke, any non-fatal major bleeding, and all-cause mortality

    Number of participants with either non-fatal ischemic or hemorrhagic stroke, any non-fatal major bleeding as defined in accordance with the International Society on Thrombosis and Hemostasis definition pertaining to major bleeding in non-surgical patients, or death due to any cause

    Measured: From time of randomization to end of observation - up to 4 years

Timeline

From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.

  1. First posted5 Mar 2019
  2. Study start9 Oct 2019
  3. Primary completionJan 2027 (estimated)
  4. Study completionJan 2027 (estimated)

Resources

More details

For doctors and researchers: how the study is designed, who runs it, and its registry IDs.

Study design
Study type
Interventional
Phase
Phase 4
Primary purpose
Prevention
Allocation
Randomised
Intervention model
Parallel groups
Model description
A multicentre, randomized, open label, parallel group study.
Masking
None (open label)
Enrolment
718 participants (estimated)
IDs, dates and publications
ClinicalTrials.gov ID
NCT03862859
Sponsor's protocol ID
DANWARD 1.26
Other IDs
2018-000484-86, 2018
Acronym
DANWARD
Status last verified
May 2026
First submitted
22 Feb 2019
Last updated
19 May 2026
Results posted
No
Data monitoring committee
Yes
FDA-regulated drug
No
FDA-regulated device
No
Individual data sharing
Yes: De-identified individual participant data for primary and secondary outcomes measures will be made available

Publications

  • Ballegaard ELF, Lindhard K, Lindhardt M, Peters CD, Thomsen Nielsen F, Tietze IN, Borg R, Boesby L, Bertelsen MC, Brosen JMB, Cibulskyte-Ninkovic D, Rantanen JM, Mose FH, Kampmann JD, Nielsen AS, Breinholt JK, Kofod DH, Bressendorff I, Clausen PV, Lange T, Kober L, Kamper AL, Bang CNF, Torp-Pedersen C, Hansen D, Grove EL, Gislason G, Dam Jensen J, Olesen JB, Hornum M, Rix M, Schou M, Carlson N. Protocol for a randomised controlled trial comparing warfarin with no oral anticoagulation in patients with atrial fibrillation on chronic dialysis: the Danish Warfarin-Dialysis (DANWARD) trial. BMJ Open. 2024 Feb 26;14(2):e081961. doi: 10.1136/bmjopen-2023-081961.

    PubMed 38413147

Questions about this trial

What is this clinical trial studying?

A Phase 4 study testing Warfarin in people with Atrial Fibrillation and Flutter and Stroke, run by Nicholas Carlson at 13 sites in Denmark.

The full registered description is in the About this study section and the official record.

Who may be eligible to take part?

The sponsor lists 3 inclusion and 24 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.

Is this clinical trial currently recruiting?

The record says: looking for participants now, as of the sponsor's last update on 19 May 2026. Status can change between updates, so confirm with the study contact before making plans.

Where is the study taking place?

The record lists 13 sites in Denmark. Whether a site is taking part right now should be confirmed with that site. See every site.

What are the possible benefits and risks?

They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.

What does this phase mean?

Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.

Not every study follows the same path, and some studies (observational studies, device studies) have no phase.

Are results available for this study?

This study is still under way. Results are not available in the source record yet.

How can a doctor refer a patient or contact the research team?

Contact Nicholas Carlson, MD PhD Ass. Prof (+45 35455927, nicholas.carlson.01@regionh.dk), or a site near the patient. AzTrials does not enrol participants or take referrals.

What does the primary outcome measure?

Primary efficacy outcome - Number of participants with transient ischemic attack, fatal and non-fatal ischaemic or unspecific stroke (time frame: From randomization to end of observation - up to 4 years). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.

Where can I read the original study information?

On the ClinicalTrials.gov record for NCT03862859, which also lists 1 linked publication.

Does a listing mean the treatment is approved or proven to work?

No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.

How often is this information updated?

AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 19 May 2026.

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