Dietary Vitamin K Variability Affects International Normalized Ratio (INR) Coagulation Indices

Couris, R. Rebecca; Tataronis, Gary; McCloskey, William W.; Oertel, Lynn B.; Dallal, Gerard E.; Dwyer, Johanna T.; Blumberg, Jeffrey B.

doi:10.1024/0300-9831.76.2.65

Cited by 61 publications

(45 citation statements)

References 29 publications

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“…Previous studies reported that as there was knowledge gap of the healthcare team with regard to warfarin-nutrient interactions which can lead to disruption in anticoagulant outcomes [8,24,25]. The finding of our study also showed that only 75.6% of the respondents answered correctly on the effect of taking large amount of leafy green vegetables (which are enrich with vitamin K), on warfarin.…”

Section: Discussionsupporting

confidence: 43%

Healthcare Professionals’ Knowledge and Counseling Practice on Warfarin Therapy at Tertiary Care Teaching Hospital, Addis Ababa, Ethiopia

Feven¹,

Demissew²,

Assefa³

2017

Cardiovasc Pharm Open Access

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Background: Warfarin has been the mainstay oral anticoagulant agent for the last several decades despite its narrow therapeutic index. It is critical for health professionals to have better knowledge and understanding on oral anticoagulant management and on how to give counseling for patients on this therapy. This study assessed healthcare professionals' knowledge and counseling practice on warfarin therapy at Tikur Anbessa Specialized Hospital (TASH).

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Section: Discussionsupporting

confidence: 43%

Healthcare Professionals’ Knowledge and Counseling Practice on Warfarin Therapy at Tertiary Care Teaching Hospital, Addis Ababa, Ethiopia

Feven¹,

Demissew²,

Assefa³

2017

Cardiovasc Pharm Open Access

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“…Even relatively small increases in vitamin K intake (150 µg/day in vitamin K-replete patients or 25 µg/day in vitamin K-depleted patients) will lower the INR [21,22]. A prospective study of 43 anticoagulated patients found that changes in vitamin K intake and variability in INR correlated and that a weekly change of 714 µg of vitamin K would alter the INR by 1 unit [24]. These data highlight the sensitivity of the therapeutic window of warfarin anticoagulation to alterations in diet.…”

Section: Discussionmentioning

confidence: 99%

Warfarin Knowledge in Patients with Atrial Fibrillation: Implications for Safety, Efficacy, and Education Strategies

et al. 2010

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Background: Multiple factors influence warfarin metabolism and can significantly affect the risk of adverse events. The extent to which patients understand the modifiable factors that impact on warfarin safety and efficacy is unclear. Methods: A 52-item questionnaire related to knowledge of warfarin was administered to patients with atrial fibrillation in a face-to-face interview with a dietitian. Results were compiled based on five categories: general warfarin knowledge, compliance, drug interactions, herbal or vitamin interactions, and diet. Results: 100 patients were surveyed. Stroke risk factors included hypertension (57%), heart failure (36%), age >75 years (33%), diabetes (22%), and prior stroke/transient ischemic attack (29%). The majority were either high-school (49%) or college graduates (27%). Ten (10%) had a stroke while on warfarin, 11 (11%) had a blood transfusion, and 26 (26%) had at least one fall. The percentages correct for questionnaire items in the five categories were as follows: general knowledge (62%), compliance (71%), drug interactions (17%), herbal or vitamin interactions (7%), and diet (23%). Neither education level nor duration of therapy correlated with warfarin knowledge. Patients at highest risk of stroke had very low knowledge scores in general. Discussion: Patients on warfarin have a poor general understanding of the medication, particularly those at highest risk of stroke.

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“…Out-of-range INR values can be a result of genetic predisposition, dietary modifications, drug interactions, and poor adherence [7][8][9]. Accordingly, it is important to evaluate patient adherence to warfarin because it is one of the modifiable factors and at the same time the evaluation can stimulate a better understanding of warfarin utilization and barriers to proper warfarin use.…”

Section: Introductionmentioning

confidence: 99%

Adherence in outpatients taking warfarin and its effect on anticoagulation control in Jordan

et al. 2016

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Background Medication adherence is an important element for the success of any therapeutic plan. The picture is more complicated with warfarin, due to its small therapeutic window and patients' needs to have effective anticoagulation control. Objective To measure warfarin-adherence, warfarin-knowledge and to assess the relationship between adherence and anticoagulation control. Setting Adult outpatients (≥18 years) taking warfarin at two medical sites in north of Jordan were invited to participate. Method This was a cross sectional study in which survey questionnaire that included demographic, clinical, warfarin related questions and Morisky Medication Adherence Scale (MMAS-8) was administered to patients in Arabic language. International normalization ratio (INR) readings were retrieved from patients' medical records. Main outcome measure MMAS-8 adherence scores and time within therapeutic range were calculated. Results More than half of study participants (54 %) were adherent (MMAS-8 = 8). The MMAS-8 adherence scores were significantly associated with warfarin-knowledge scores (Spearman's ρ = 0.291, p = 0.000). Adherent patients were more likely to have good anticoagulation control compared to non-adherent patients (MMAS-8 ≤ 7). Conclusion Adherence to warfarin therapy can have a substantial effect on anticoagulation control. Thus, healthcare practitioners should consider strategies to improve patient adherence to warfarin.

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Dietary Vitamin K Variability Affects International Normalized Ratio (INR) Coagulation Indices

Abstract: Patients taking warfarin and consuming markedly changing amounts of vitamin K may have a variable weekly INR with potentially unstable anticoagulant outcomes.

Cited by 61 publications

References 29 publications

Healthcare Professionals’ Knowledge and Counseling Practice on Warfarin Therapy at Tertiary Care Teaching Hospital, Addis Ababa, Ethiopia

Healthcare Professionals’ Knowledge and Counseling Practice on Warfarin Therapy at Tertiary Care Teaching Hospital, Addis Ababa, Ethiopia

Warfarin Knowledge in Patients with Atrial Fibrillation: Implications for Safety, Efficacy, and Education Strategies

Adherence in outpatients taking warfarin and its effect on anticoagulation control in Jordan

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