Evidence map›Paper›PMID 41528716›Full record

ArticleInternational journal of clinical pharmacy2026

Fixed dose versus 3-day loading dose warfarin initiation in atrial fibrillation: effects on INR stabilization and time in the therapeutic range.

Sharifah Nadiah Syed Hamzah, Shahrul Aiman Soelar, Sabariah Noor Harun

Abstract readMulticenter StudyComparative Study
In one paragraph

Article in International journal of clinical pharmacy, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

3 authors.

Sharifah Nadiah Syed HamzahDiscipline of Clinical Pharmacy, School of Pharmaceutical Sciences, Universiti Sains Malaysia, Pulau Pinang, Malaysia. shnadiah@gmail.com.ORCID http://orcid.org/0009-0005-7592-4587
Shahrul Aiman SoelarClinical Research Center, Hospital Sultanah Bahiyah, Ministry of Health Malaysia, Alor Setar, Kedah, Malaysia.ORCID http://orcid.org/0000-0003-1025-8809
Sabariah Noor HarunDiscipline of Clinical Pharmacy, School of Pharmaceutical Sciences, Universiti Sains Malaysia, Pulau Pinang, Malaysia. sabariahnoor@usm.my.ORCID http://orcid.org/0000-0001-8476-7425

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

introductionWarfarin initiation strategies vary, with some clinicians using either a fixed-dose or loading-dose regimen to achieve therapeutic anticoagulation. However, evidence comparing their effectiveness in multiethnic Asian populations without genotype-guided dosing remains limited.

aimTo compare a fixed-dose regimen with a 3-day loading-dose regimen in terms of international normalized ratio (INR) stability and time in the therapeutic range (TTR) over 12 months in a multiethnic atrial fibrillation (AF) cohort. We also aimed to evaluate the relationship between the time to initial INR stabilization and the subsequent anticoagulation quality.

methodThis multicenter, retrospective cohort study included 780 warfarin-naïve patients with AF from two tertiary hospitals (2010 to 2022). Patients were grouped by the initiation strategy: fixed-dose (n = 501) or 3-day loading-dose (n = 279). The primary outcome was the TTR at 3, 6, and 12 months. The association between time to INR stabilization and TTR was assessed using Spearman's correlation, and a General Linear Model (GLM) was used to adjust for comprehensive demographic and clinical confounders.

resultsThe time to initial INR stabilization showed a strong inverse correlation with TTR across all time points (Spearman's r = -0.600 to -0.710; p < 0.001). Although the unadjusted analysis suggested that the INR stabilized faster in the loading-dose group (mean: 111.8 vs. 138.6 days; p < 0.001), this difference became insignificant after accounting for confounding factors (adjusted mean: 94.1 vs 104.1 days; p = 0.248). Similarly, adjusted means of TTRs did not differ significantly between regimens at 3, 6, or 12 months.

conclusionThe choice between fixed-dose and loading-dose warfarin initiation strategies does not independently influence long-term anticoagulation control. Instead, time to initial INR stabilization is the strongest predictor of TTR quality over 12 months. Clinical efforts should prioritize early and intensive INR monitoring in settings without genotype-guided dosing, as both baseline characteristics and the ongoing clinical management likely determine anticoagulation outcomes.

Indexed as

AnticoagulantsAtrial FibrillationInternational Normalized RatioWarfarinAgedAged, 80 and overCohort StudiesDose-Response Relationship, DrugDrug Administration ScheduleFemaleHumansMaleMiddle AgedRetrospective StudiesTime FactorsAnticoagulantsWarfarinAtrial fibrillationFixed doseINR stabilizationLoading doseTime in therapeutic rangeWarfarin initiation

Identifiers

PMID41528716
PMCPMC13176140

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