The efficacy of low-dose warfarin initiation (3 mg versus 5 mg) in newly diagnosed venous thromboembolism patients among a population with a high prevalence of warfarin-sensitive haplotype of the VKORC1 gene: a randomized controlled trial
Issued Date
2022-01-01
Resource Type
ISSN
10245332
eISSN
16078454
Scopus ID
2-s2.0-85123495039
Pubmed ID
35068386
Journal Title
Hematology (United Kingdom)
Volume
27
Issue
1
Start Page
95
End Page
104
Rights Holder(s)
SCOPUS
Bibliographic Citation
Hematology (United Kingdom) Vol.27 No.1 (2022) , 95-104
Suggested Citation
Suwanawiboon B. The efficacy of low-dose warfarin initiation (3 mg versus 5 mg) in newly diagnosed venous thromboembolism patients among a population with a high prevalence of warfarin-sensitive haplotype of the VKORC1 gene: a randomized controlled trial. Hematology (United Kingdom) Vol.27 No.1 (2022) , 95-104. 104. doi:10.1080/16078454.2021.2019891 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/87436
Title
The efficacy of low-dose warfarin initiation (3 mg versus 5 mg) in newly diagnosed venous thromboembolism patients among a population with a high prevalence of warfarin-sensitive haplotype of the VKORC1 gene: a randomized controlled trial
Author(s)
Author's Affiliation
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Abstract
Objectives: The fact that a lower warfarin maintenance dose is required by Asian populations is well-known. Currently, the American College of Chest Physicians recommends commencing warfarin at a dose between 5 and 10 mg for venous thromboembolism (VTE). However, the optimal initiating dose in Asians is unknown. This study aimed to evaluate the efficacy of a 3 mg versus a 5 mg of warfarin initiating dose and a corresponding nomogram in patients with VTE. Methods: Eligible patients were randomized to receive 3 mg or 5 mg per day warfarin for the first 2 days of treatment. The subsequent dose was adjusted according to the warfarin nomogram. The primary outcome was the number of patients who achieved an INR 2.0–3.0 within 8 days. Results: Fifty-six patients were enrolled. There was no significant difference in baseline characteristics between the groups. Seventeen (60.7%) patients in the 3-mg group and 22 (78.6%) patients in the 5-mg group achieved a therapeutic INR within 8 days (p = 0.146). However, there were significantly more patients in the 5-mg group who achieved the target INR on day 5 (53.6% vs 25.0%, p = 0.029). Furthermore, VKORC1-1639G > A was associated with an increased likelihood to achieve the target INR within 5 days (OR 3.81, 95%CI 1.19–12.16, p = 0.021). Conclusions: The efficacy of a 3 mg warfarin starting dose with subsequent dose adjustment was similar to that of 5 mg on day 8 after warfarin initiation. However, a 5 mg initiating dose resulted in more patients who achieved therapeutic INR on day 5.