Factors Affecting Warfarin-Related Knowledge and INR Control of Patients Attending Physician- and Pharmacist-Managed Anticoagulation Clinics

• Published in: Journal of pharmacy practice 2011-10, Vol.24 (5), p.485-493
• Main Authors: Hasan, Syed S., Shamala, R., Syed, Imran A., Basariah, N., Chong, David W. K., Mei, Teh K., Chin, Ong H.
• Format: Article
• Language: English
• Subjects: Adult; Age Factors; Aged; Aged, 80 and over; Ambulatory Care Facilities - organization & administration; Anticoagulants - administration & dosage; Attitude of Health Personnel; Blood Coagulation - drug effects; Cross-Sectional Studies; Drug Monitoring; Female; Health Knowledge, Attitudes, Practice; Humans; International Normalized Ratio; Malaysia; Male; Middle Aged; Pharmacists; Physicians; Professional Role; Sex Factors; Surveys and Questionnaires; Warfarin - administration & dosage; Young Adult
• ISSN: 0897-1900; 1531-1937
• DOI: 10.1177/0897190011415684

Objectives: To assess the anticoagulation knowledge and international normalized ratio (INR) control among patients on warfarin. Methods: A cross-sectional study with 156 randomly sampled patients from physician- (non-medication therapy adherence clinic [non-MTAC]) and pharmacist (MTAC)-run anticoagulation clinics using a validated interviewer-administered questionnaire. Patients' INR readings from 2008 to 2010 were recorded. Results: Patients on warfarin scored an average of 66.5% ± 36.0% for their knowledge on how warfarin works, 42.9% ± 44.9% for interaction between warfarin and alcohol, and 49.2% ± 21.1% for adverse effects. No significant differences were found between MTAC and non-MTAC patients on their knowledge. There was a negative correlation between patients' knowledge and age (P = .001, r s = −.293) and a positive correlation between patients' knowledge and education level (P = .001, r s = .365). MTAC patients were found to have better INR control than non-MTAC when compared for mean percentage days in range (63.4% ± 18.9% vs 52.5% ± 18.2%; P = .006) and mean percentage visits in range (58.8% ± 17.9% vs 46.8% ± 18.6%; P = .001). Conclusions: MTAC patients were found to have better INR control compared to non-MTAC patients. A joint cooperation between physicians, pharmacists, and nurses should exist to achieve desired therapeutic outcomes.