Impact of Genotype-Guided Dosing on Anticoagulation Visits for Adults Starting Warfarin: A Randomized Controlled Trial

Abstract

Aim: This study aimed to assess the effectiveness of genotype-guided warfarin dosing. Patients & methods: A total of 109 adults were randomized to receive initial dosing as determined by an algorithm containing genetic (VKORC1 and CYP2C9) plus clinical information or only clinical information. Primary end points were the number of anticoagulation visits and the time in therapeutic range (TTR) over 90 days. Secondary end points included time to therapeutic dose, International Normalized Ratios of >4, emergency visits, hospitalizations, hemorrhagic events, thrombotic events and mortality. Results: Neither primary end point was significantly different between groups (anticoagulation visits: 6.96 vs 6.37, p = 0.51; TTR: 0.40 vs 0.43, p = 0.59). Fewer emergency visits, hospitalizations, major hemorrhagic events, thrombotic events and deaths occurred in the genetic plus clinical group than in the clinical only group, but these differences were not statistically significant. Conclusion: Genotype-guided dosing did not decrease the number of anticoagulation visits or improve TTR. Our trial was not powered to detect anything but large differences for utilization and health outcomes.

Original submitted 7 January 2013; Revision submitted 27 July 2013

KEYWORDS::

• anticoagulation
• clinical trial
• genetics
• pharmacogenetics
• pharmacogenomics
• warfarin

Financial & competing interests disclosure

This work was supported by the Investments for the Future award from the University of North Carolina Chapel Hill Office of the Dean and the University of North Carolina Institute for Pharmacogenomics and Individualized Therapy. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Ethical conduct of research

This trial was approved by the University of North Carolina at Chapel Hill institutional review board and registered on clinicaltrials.gov (NCT00904293). Informed consent has been obtained from the participants involved.

Additional information

Funding

This work was supported by the Investments for the Future award from the University of North Carolina Chapel Hill Office of the Dean and the University of North Carolina Institute for Pharmacogenomics and Individualized Therapy. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed. No writing assistance was utilized in the production of this manuscript.