Pharmacogenomics of Warfarin in Hispanics and Latinos
| Status: | Recruiting |
|---|---|
| Conditions: | Cardiology |
| Therapuetic Areas: | Cardiology / Vascular Diseases |
| Healthy: | No |
| Age Range: | 18 - Any |
| Updated: | 1/27/2019 |
| Start Date: | September 2016 |
| End Date: | September 2020 |
| Contact: | Jason H Karnes, PharmD, PhD |
| Email: | karnes@pharmacy.arizona.edu |
| Phone: | 520-626-1447 |
Warfarin is a commonly used blood thinner to treat and prevent blood clots. It is important
to take the right dose of warfarin because too much can increase the risk of bleeding and too
little can increase the risk of blood clots. This is why patients are closely monitored
especially when they begin warfarin therapy. When clinicians prescribe warfarin, they have to
consider different factors such as patient's age, body size, diet, and other medications that
can interact with warfarin.
Certain genes have also been found to affect warfarin dose. Individuals have variations in
these genes, which can help explain why some patients need higher dose and others require
less. These factors have been used to better predict a patient's warfarin dose requirement.
However, these predictions were created based on Caucasian populations and they may not be
accurate in predicting a safe warfarin dose if a patient is not Caucasian. This study aims to
identify new genetic variation that affects warfarin dosing in Hispanic and Latino
populations and try to better predict a Hispanic or Latino patient's warfarin dose
requirement.
to take the right dose of warfarin because too much can increase the risk of bleeding and too
little can increase the risk of blood clots. This is why patients are closely monitored
especially when they begin warfarin therapy. When clinicians prescribe warfarin, they have to
consider different factors such as patient's age, body size, diet, and other medications that
can interact with warfarin.
Certain genes have also been found to affect warfarin dose. Individuals have variations in
these genes, which can help explain why some patients need higher dose and others require
less. These factors have been used to better predict a patient's warfarin dose requirement.
However, these predictions were created based on Caucasian populations and they may not be
accurate in predicting a safe warfarin dose if a patient is not Caucasian. This study aims to
identify new genetic variation that affects warfarin dosing in Hispanic and Latino
populations and try to better predict a Hispanic or Latino patient's warfarin dose
requirement.
If the patient is willing to hear about the study, during routine clinical care, one of the
patient's providers will approach patients meeting the study criteria about participation in
the study. Study personnel will not approach potential participants unless permission is
given to the patient's provider. If the patient would like to participate in the study, study
personnel will discuss details of the study in person during the patient's routine clinical
care visit. There will also be a flyers available for posting and for distribution to
potential participants.
Participants consenting to the study will be asked to provide a cheek swab or mouthwash
sample to provide buccal cells for DNA extraction. If the patient is receiving a blood draw
during their regular clinical appointment, participants will be asked for a blood sample of
15 milliliters. Genomic DNA will be isolated for genotyping and patient plasma samples will
also be stored.
Linear regression will be used to test association of SNPs with therapeutic warfarin dose
using the algorithms derived by the International Warfarin Pharmacogenomics Consortium. The
primary phenotype (weekly stable warfarin dose) will be transformed by square root. SNPs and
other variables associated with warfarin dose will be assessed in univariate analyses and
entered into stepwise linear regression to determine the adjusted association with dose
requirements using R2. Quality control procedures will include deviation from Hardy-Weinberg
Equilibrium, and SNP and sample exclusions based on call rates. Ancestry-informative marker
(AIM) analysis will be performed to estimate ancestry in each individual.
patient's providers will approach patients meeting the study criteria about participation in
the study. Study personnel will not approach potential participants unless permission is
given to the patient's provider. If the patient would like to participate in the study, study
personnel will discuss details of the study in person during the patient's routine clinical
care visit. There will also be a flyers available for posting and for distribution to
potential participants.
Participants consenting to the study will be asked to provide a cheek swab or mouthwash
sample to provide buccal cells for DNA extraction. If the patient is receiving a blood draw
during their regular clinical appointment, participants will be asked for a blood sample of
15 milliliters. Genomic DNA will be isolated for genotyping and patient plasma samples will
also be stored.
Linear regression will be used to test association of SNPs with therapeutic warfarin dose
using the algorithms derived by the International Warfarin Pharmacogenomics Consortium. The
primary phenotype (weekly stable warfarin dose) will be transformed by square root. SNPs and
other variables associated with warfarin dose will be assessed in univariate analyses and
entered into stepwise linear regression to determine the adjusted association with dose
requirements using R2. Quality control procedures will include deviation from Hardy-Weinberg
Equilibrium, and SNP and sample exclusions based on call rates. Ancestry-informative marker
(AIM) analysis will be performed to estimate ancestry in each individual.
Inclusion Criteria:
- At least 18 years of age
- Ability to give informed consent
- Therapeutic INR for at least 2 consecutive clinic visits
- Self-identifies as Hispanic or Latino
Exclusion Criteria:
- Less than 18 years old
- Unable to give informed consent
- Severe hepatic impairment
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