Introduction As believed, the dailysupplementation with low-dose of vitamin K might improve anticoagulationcontrol, which caused difficulties in managing warfarin therapy. This study wasreviewing the previous medical studies, in order to conduct whether reducingvitamin K supplementation can deduce the detrimental in clinically used of VKA.Moreover, it also conducts the effect of daily low-dose vitamin K supplement onmajor bleeds, thromboembolic events and in stabilizing International normalizedratio (INR) in the patients who were taking VKAs. As a result of drug and foodinteraction, monitoring the anticoagulant effect of VKAs by using INR areneeded that INR is a response to warfarin therapy which influenced by intake ofvitamin K. Method This study used the patients who are older than 18 years and on VKAtherapy.
All controlled trials studies are randomized and published between1970 and August 2012. The criteria of this study were included the studies thatcompared pharmaceutically prepared vitamin K supplement to placebo. The outcomesinterested in the rate of haemorrhagic and thromboembolic events as well asestimate the time in therapeutic range (TTR). Two independent reviewers only reviewedEnglish language full-text articles that were included VKA therapy and involvesthe daily use of vitamin K.
The used in the Grading of RecommendationsAssessment, Development and Evaluation (GRADE) system is to access the qualityof evidence. Result Only three of the articles were included in the study. The otherexcluded articles do not meet the criteria; therefore, no relevant studies canbe identified from the reference lists of review articles. The results in allthree articles reported TTR as an outcome, which is higher in the patients who werereceiving vitamin K supplements.
As well as the INR control were 3.5 % morethan patients who were receiving placebo. The report from the trials, thebleeding is not verifying and no clear definition of thromboembolic events. Conclusion The systematic reviews show Vitamin K supplements are not useful inimproving the stability of INR control in patients receiving VKAs. The studyhas limitation caused by a small number of included trials and the group ofpatients with poor INR control are lacked studied.
The reviewers may also havemissed the relevant studies which are written in the language other thanEnglish. The quality of evidence was rated as low due to the risk of bias andimprecision. These results insufficiently suggested that the daily low-dosevitamin K supplements are useful in strengthening the outcome of stabilizingINR control.