Warfarin Quality, Adherence, Range, Determinants, and Events in Egyptian Rheumatic Heart Disease and Atrial Fibrillation (WARDEN-Egypt)

September 13, 2026 updated by: Mariam Syacoub, Assiut University

Time in Therapeutic Range, Predictors of Poor Anticoagulation Control, and Clinical Outcomes in Egyptian Patients With Rheumatic Heart Disease and Atrial Fibrillation on Warfarin: A Single Center Retrospective-Prospective Cohort Study

No Egyptian study has systematically quantified TTR, identified its predictors, or linked anticoagulation quality to clinical outcomes in the RHD-AF population. This knowledge gap directly impairs the ability of Egyptian cardiac centers to design effective anticoagulation clinic models.16 WARDEN-Egypt addresses a precisely defined evidence gap at zero marginal cost: the study relies entirely on INR logbooks already maintained in clinical practice and structured follow-up visits that replicate current standard of care. Its findings will provide the first Egyptian TTR benchmark, identify modifiable predictors of poor anticoagulation control amenable to targeted intervention, and generate hypothesis-forming data on the TTR-outcome relationship. This has direct implications for anticoagulation clinic design, national guideline development, and future interventional trials in Egyptian RHD.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

Rheumatic heart disease (RHD) remains the most prevalent acquired cardiac condition in low- and middle-income countries (LMICs), disproportionately affecting young adults in sub-Saharan Africa, South Asia, and the Middle East.1-3 In Egypt, RHD continues to be a leading cause of cardiac morbidity, particularly among women of reproductive age and rural populations with limited access to primary prophylaxis.4,5 Atrial fibrillation (AF) is among the most frequent and clinically dangerous complications of RHD. Unlike non-valvular AF, RHD-AF carries a substantially higher thromboembolic risk - estimated at five to twenty times that of the general population.6 Mitral stenosis is the dominant lesion predisposing to AF and left atrial thrombus formation. For these patients, anticoagulation with vitamin K antagonists (VKAs) remains the standard of care.7 The INVICTUS trial (2022), the largest randomized controlled trial in RHD-AF, definitively established that warfarin is superior to rivaroxaban in patients with RHD-associated AF. The warfarin arm demonstrated significantly lower rates of the composite primary endpoint (stroke, systemic embolism, myocardial infarction, or death from vascular or unknown cause) compared to rivaroxaban (8.2% vs. 12.2% per 100 patient-years; HR 0.65, 95% CI 0.58-0.73; p<0.001). Direct oral anticoagulants (DOACs) are therefore not recommended in RHD-AF, cementing the central role of warfarin in this population for the foreseeable future.5 Warfarin efficacy is critically dependent on the quality of anticoagulation control, best captured by time in therapeutic range (TTR) - the proportion of time that a patient's INR remains within the target range (typically 2.0-3.0 for RHD-AF). TTR calculated by the Rosendaal linear interpolation method is the accepted standard.9

Study Type

Observational

Enrollment (Estimated)

90

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Egypt
    • Asyut Governorate
      • Asyut, Asyut Governorate, Egypt
        • Assiut University Heart Hospital, Assiut, Egypt
        • Contact:
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

: the study relies entirely on INR logbooks already maintained in clinical practice and structured follow-up visits that replicate current standard of care. Its findings will provide the first Egyptian TTR benchmark, identify modifiable predictors of poor anticoagulation control amenable to targeted intervention, and generate hypothesis-forming data on the TTR-outcome relationship. This has direct implications for anticoagulation clinic design, national guideline development, and future interventional trials in Egyptian RHD.

Description

Inclusion Criteria:

  • Inclusion Criteria

    1. Age ≥18 years
    2. Confirmed diagnosis of rheumatic heart disease (echocardiographic evidence of rheumatic valve morphology, prior history of rheumatic fever, or cardiology consultant diagnosis recorded in medical records)
    3. Electrocardiographically or holter-confirmed atrial fibrillation (paroxysmal, persistent, or permanent)
    4. On warfarin therapy for at least 6 consecutive months prior to enrollment with the intent to continue
    5. At least 3 recorded INR values in the preceding 12 months in the center's logbook (minimum data requirement for Rosendaal TTR calculation)
    6. Willingness to attend scheduled follow-up visits for 12 months and to provide written informed consent

Exclusion Criteria: 1. Anticipated cardiac surgery, valvuloplasty, or cardioversion within the next 6 months 2. Pregnancy or planned pregnancy during the study period 3. Active malignancy or other life-limiting condition with expected survival <12 months 4. Current or recent (≤12 months) use of a direct oral anticoagulant or heparin as primary anticoagulation 5. Severe hepatic impairment (Child-Pugh C) or known bleeding diathesis 6. Residence in a geographic area making 12-month follow-up participation unreasonably burdensome (as judged by the site investigator) 7. Fewer than 3 documented INR values in the preceding 12 months (insufficient data for Rosendaal TTR calculation) 6. Presence of a mechanical prosthetic heart valve (MPHV) in any position (aortic or mitral), regardless of thrombogenicity category. Patients with bioprosthetic (tissue) valves are not excluded, provided the prescribed INR target is 2.0-3.0 and all other inclusion criteria are met.

Patients with mechanical prosthetic heart valves (MPHVs) are excluded from this study. With all enrolled patients having native RHD-AF, a uniform INR therapeutic target of 2.0-3.0 applies to every participant, eliminating patient-specific target adjustments and rendering valve type non-informative as an analytical predictor. The overwhelming majority of warfarin-treated RHD-AF patients at Assiut University Heart Hospital have rheumatic mitral stenosis as the dominant lesion, making this a clinically homogeneous and internally valid study population. Patients with bioprosthetic (tissue) valves on warfarin for AF are not excluded, provided their prescribed INR target is 2.0-3.0 and all other inclusion criteria are satisfied.

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Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Primary Endpoints: (1) Mean TTR by Rosendaal linear interpolation; (2) Predictors of poor TTR (TTR <65%)
Time Frame: 12 months of archived INR data extracted at enrollment
12 months of archived INR data extracted at enrollment

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Assiut University

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

Helpful Links

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

October 1, 2026

Primary Completion (Estimated)

October 1, 2027

Study Completion (Estimated)

October 1, 2028

Study Registration Dates

First Submitted

September 13, 2026

First Submitted That Met QC Criteria

September 13, 2026

First Posted (Actual)

September 17, 2026

Study Record Updates

Last Update Posted (Actual)

September 17, 2026

Last Update Submitted That Met QC Criteria

September 13, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • TTR in RHD and AF in egypt

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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