Association between TTR-INR guided warfarin adjustment protocol and time in therapeutic range (TTR) in patients with atrial fibrillation receiving vitamin K antagonist oral anticoagulant

Status

Active, not recruiting

Phases

Phase 3

Study type

Interventional

Source

TCTR

Registry ID

TCTR20201224003

Enrollment

150

Registered

2020-12-24

Start date

2021-01-01

Completion date

Unknown

Last updated

2026-08-03

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Patient with atrial fibrillation Atrial fibrillation (AF) Time in therapeutic range (TTR) International normalized ratio (INR) Vitamin K antagonist (VKA) Oral anticoagulants (OACs) Non&#45

Interventions

Classify Participant to 2 groups 1. TTR = 70% All participants adjusted warfarin dose at Warfarin Clinic&#44

King Chulalongkorn Memorial Hospital (KCMH) by using TTR&#45

INR guided warfarin adjustment protocol (Warfarin Dosing Nomogram). Correct INR and calculated TTR (Rosendaal method) Evaluate outcome at 1 year &#45

TTR change before and after protocol implementation

Experimental Drug

TTR&#45

INR guided warfarin adjustment protocol (Warfarin Dosing Nomogram)

Eligibility

Sex/Gender

All

Age

18 Years to No maximum

Inclusion criteria

Inclusion criteria: 1. Adult patients (age â‰¥18 years) 2. Followed up at warfarin clinic in KCMH 3. Diagnosed with non-valvular atrial fibrillation (confirmed by 12-lead ECG or ECG strip with â‰¥30 seconds of AF, including wearable-recorded ECGs) 4. Using warfarin for at least 2 years 5. Have at least 3 INR per year readings previously for TTR calculation

Exclusion criteria

Exclusion criteria: 1. Rheumatic mitral valve disease 2. Prosthetic valve or valve repair 3. Atrial fibrillation related to transient reversible cause (e.g., during respiratory tract infection) 4. Participation in any other clinical trial 5. Pregnancy 6. History of use DOACs within 2 years 7. Not available to attend follow-up 8. Refusal to participate

Design outcomes

Primary

Measure	Time frame
Proportion of TTR change after protocol implementation 1 year Unpaired t test	—

Secondary

Measure	Time frame
Protocol feasibility 1 year Questionnaire,Incidence of bleeding and thromboembolic event 1 year Percent	—

Countries

Thailand

Contacts

Public ContactPaisit Kosum

Faculty of Medicine, Chulalongkorn University

johndevil7@hotmail.com66821642440

Outcome results

None listed

Source: TCTR (via WHO ICTRP) · Data processed: Aug 9, 2026

Association between TTR&#45;INR guided warfarin adjustment protocol and time in therapeutic range (TTR) in patients with atrial fibrillation receiving vitamin K antagonist oral anticoagulant