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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.