Category: Professional Posters
Purpose: The dose of warfarin required to keep patients within the desired therapeutic range is dependent on many patient-specific factors. Liver volume, determined by ultrasound, appears to have a positive correlation with warfarin dosing requirements. Patient height also has a positive correlation with liver size. Moreover, patient height is correlated with foot length. Therefore, the size of a patient’s foot may be a representation for liver size, which may have a positive correlation with warfarin dose requirements. The purpose of this study is to examine the relationship between weekly warfarin dose and patients’ shoe size.
Methods: This retrospective evaluation occurred between June 2017 and January 2018. Patients were identified from a generated report using e-Clinical Works and were included if they were a patient of the anticoagulation clinic at AtlantiCare Regional Medical Center (ARMC) and were prescribed warfarin. Patients were excluded if they were over the age of 65, had a history of coagulopathy, significant drug interactions, documented dietary issues, and comorbidities affecting warfarin. Those included had a therapeutic International Normalized Ratio (INR) of 2-3. Medical records were reviewed and data collection included gender, age, weekly warfarin dose, height, weight, and shoe size per patient interview and observation. Body Mass Index (BMI), ethnicity, comorbidities, coagulopathies, and potential drug interactions were also recorded. The Pearson correlation coefficient was used to determine a relationship between patients’ total weekly dose of warfarin and shoe size.
Results: Forty-seven patients were included in our analysis with an average age of 55 years (range 29 to 65 years) with 34 males (72.4 percent). The average weekly warfarin dose, height, weight and shoe size were 51.6 milligrams (mg), 174 centimeters (cm), 97.8 kilograms (kg) and 10, respectively. Statistical analysis was utilized to compare weekly warfarin dose with age, gender, weight, BMI, height, and shoe size. There was a negative correlation between weekly dose and age (r= -0.4663; P = 0.0013). There was a positive, direct correlation between weekly dose and BMI (r = 0.3481; P = 0.019), shoe size and height (r = 0.7665; P = < 0.0001), and weekly dose and shoe size (r = 0.3377; P = 0.0202).
Conclusion: The results of this study provide evidence of a relationship between weekly warfarin dose and patient’s shoe size in adults 65 years of age or younger. The clinical application of our findings is limited since multiple variables may impact warfarin dosing requirement. Further studies are warranted with a larger sample size to confirm if shoe size is a predictor of warfarin dosing.