January 28, 2014 — University of Wyoming School of Pharmacy P4 student Tracey Le,
from Anaheim, California, attended the American Society of Health-System Pharmacists
(ASHP) Midyear meeting December 6–10 in Orlando, Florida, where she gave a poster
presentation titled, "Assessment of the Knowledge and Awareness of Diet and Other
Weight Loss Strategies in Patients Enrolled in an Anticoagulation Clinic." Le worked
with Clinical Associate Professor of Pharmacy Practice Jaime Hornecker, Pharm.D.,
BCPS, to assess the knowledge of patients enrolled in an anticoagulation clinic at
the UW Family Practice Clinic in Casper, Wyoming, regarding weight loss strategies,
how they interact with warfarin therapy, and the clinical significance of these interactions.
Warfarin (Coumadin) is a widely used anticoagulant that requires significant patient
education and monitoring. Many diet- and medication-related changes affect warfarin
therapy. The purpose of this research project was to assess the knowledge of patients
enrolled in an anticoagulation clinic regarding weight loss strategies, such as high
protein, low carbohydrate diets, weight loss shakes, and OTC and herbal weight loss
products; how they interact with warfarin therapy, and the clinical significance of
these interactions. Regarding specific weight loss diets, several case reports have
been published about low-carbohydrate, high-protein diets interacting with warfarin
therapy by decreasing INR.
The pharmacist-managed Anticoagulation Clinic at the University of Wyoming Family
Practice Clinic in Casper, Wyoming, monitors over 100 patients on warfarin therapy,
and mainly serves indigent patients who are self-pay or utilizing sliding scale discounts
for services. Any patient visiting the Anticoagulation Clinic for monitoring was asked
to participate and complete a 17-question survey. Informed consent was obtained from
all subjects. A series of questions assessed patient knowledge relating warfarin to
use of alcohol, smoking, activity, diet, weight loss shakes and powders, herbal products
marketed for weight loss, weight loss supplements or medications, and weight loss
monitoring programs. Data was analyzed to determine overall patient knowledge, significance
of possible interactions of warfarin with various weight loss strategies, and areas
for patient education. The proposal involved research which was exempt from review
by the Institutional Review Board for projects involving human subjects because the
research involved minimal risk.
A total of 41 patients completed the survey. Most patients reported they did not attempt any weight loss strategies. Patients who reported attempting weight loss used green tea, raspberry ketones, exercise, low carbohydrate and high protein diets, and various other methods. Those who reported using weight loss strategies, however, did not notice a consistent effect on their anticoagulation therapy. Most patients reported varied effects on their INR while attempting weight loss. This may be due to their lack of attention to the changes in their INR because they were not expecting protein shakes or diets to affect their anticoagulation therapy. The primary endpoint of this study was inconclusive; however, due to the nature of the survey, the study showed there is a large opportunity for pharmacists to educate their patients. For example, 32% (n=13) of patients were not sure of the effect of alcohol on INR, 49% (n=20) of patients were not sure of the effect of tobacco on INR, and 78% (n=32) of patients were incorrect or unsure of the effect of ideal protein diets on INR.