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Completed

NCT Number: NCT00634907

Prospective Genotyping For Total Hip or Knee Replacement Patients Receiving Warfarin (Coumadin)

Several human genes affect how medications are metabolized by the body. It is believed that knowledge of variations of these genes can help health care providers better manage an anticoagulation medicine called warfarin (Coumadin®)and as a result decrease patient problems with bleeding or the development of blood clots. This study was designed to evaluate if genetic testing can improve warfarin initiation better than usual care.

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Key information

Conditions

Venous Thromboembolism Bleeding Cardiovascular Diseases Embolism and Thrombosis Hemorrhage Pathologic Processes Pathological Conditions, Signs and Symptoms Thromboembolism Vascular Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

University of Utah Health Care

Salt Lake City, Utah, 84132, United States

About this study

This study was completed in 2008 and was published. Consult the citation link for more details.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Participants were otherwise healthy adults (≥ 18 years of age) who were planning total hip or knee replacement or revision surgery at the University of Utah Hospital, and scheduled a pre-operative office visit at the University of Utah Orthopaedic Center.

Exclusion criteria

  • Blood transfusion in previous two weeks
  • Participant is already taking warfarin
  • Pre-operative INR > 4.0
  • Pre-operative bilirubin > 2.4 mg/dL
  • Current active cancer diagnosis with ongoing treatment
  • Concomitant medications known to exert a major interaction with warfarin such as septra, metronidazole, tramadol, amiodarone, ciprofloxacin, or cimetidine.

Treatment and study plan

Pharmacogenetic-based warfarin dosing

Genetic

Prior to elective joint replacement surgery a blood sample is collected for genetic information(genotyping)which was used for calculating warfarin doses for patients randomized to the cytochrome arm. Outcomes in terms of efficacy, safety, and management of warfarin were compared between this group and the group in which warfarin doses are determined per usual care.

NOTE: Standard of care for elective knee and hip replacement at our institution is to receive post-operative warfarin thromboprophylaxis. Administration of warfarin was not specific to this study, nor was the duration of prophylaxis, however, warfarin dosing was influenced by the study arm as noted above.

Usual care warfarin dosing

Other

For patients in arm 2, the control group, warfarin dosing is per usual care. Outcomes in terms of safety, efficacy, and warfarin management was compared to that of patients in the other arm, who receive warfarin dosing based on genotyping.

NOTE: Standard of care for elective knee and hip replacement at our institution is to receive post-operative warfarin thromboprophylaxis. Administration of warfarin was not specific to this study, nor was the duration of prophylaxis, however, warfarin dosing was influenced by the study arm as noted above.

Primary outcomes

  1. The Number of Participants With Adverse Events Associated With Warfarin Anticoagulation Following Total Hip and Total Knee Replacement

    Time frame: 90 days post surgery

    Adverse events were defined as

    • Major bleeding: fatal bleeding, bleeding into a critical organ, bleeding that requires hospital admission
    • Minor bleeding: clinically overt bleeding not meeting criteria for major bleeding
    • Symptomatic deep vein thrombosis (DVT)
    • Pulmonary embolism (PE)

Secondary outcomes

  1. Percentage of Determinations in Therapuetic Range (INR 1.8-2.9)

    Time frame: 2 weeks (knee arthroplasty) or 4 weeks (hip arthroplasty)

    Patient response to warfarin was evaluated based on the international normalized ratio (INR), calculated from a prothrombin time blood test. When the INR value was between 1.8 and 2.9, the patient was considered to be "therapeutic." The proportion of INR determinations that fell within the therapeutic range (INR between 1.8-2.9) was calculated, per arm, based on total number of INR determinations that were made during treatment with warfarin.

  2. Percentage of Determinations Subtherapeutic (INR<1.8)

    Time frame: 2 weeks (knee arthroplasty) or 4 weeks (hop arthroplasty)

    Patient response to warfarin was evaluated based on the international normalized ratio (INR), calculated from a prothrombin time blood test. When the INR value was less than 1.8, the patient was considered to be "subtherapeutic." The proportion of INR determination that were subtherapeutic was caluculated, per arm, based on the total number of INR determinations that were made during treatment with warfarin.

  3. Percentage of Determinations Supratherapeutic (INR>2.9)

    Time frame: 2 weeks (knee arthroplasty) or 4 weeks (hip arthroplasty)

    Patient response to warfarin was evaluated based on the international normalized ratio (INR), calculated from a prothrombin time blood test. When the INR value was greater than 2.9, the patient was considered to be "supratherapeutic." The proportion of INR determinations that were supratherapeutic was calculated, per arm, based on total number of INR determinations that were made during treatment with warfarin.

Sponsors and collaborators

Lead sponsor

Gwen McMillin

Other

Registry information

Official study title

Prospective CYP2C9 And VKORC1 Genotyping For Total Hip or Knee Replacement Patients Receiving Warfarin (Coumadin)For Anticoagulation

Important dates

Study start
2006
Primary completion
2008
Study completion
2008
First posted
Mar 13, 2008
Registry last updated
Jun 8, 2017

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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