Risk Factors Affecting INR Control and Development of Patient Care Strategies for Warfarin Users at Sung Men Hospital, Phrae Province

Abstract

This action research aimed to identify the risk factors causing International Normalized Ratio (INR) levels to fall outside the target range among patients on warfarin therapy, while also developing systematic pharmaceutical care guidelines to optimize patient outcomes. The study monitored a group of 225 patients attending the Warfarin Clinic at Sung Men Hospital in Phrae Province between August 2024 and May 2025. Information was gathered through patient interviews, focus group discussions, and clinical INR records retrieved directly from the HOSxP system, with data subsequently analyzed using descriptive statistics.

The findings revealed that the primary triggers for unstable INR levels were dietary habits, medication non-adherence, and the inappropriate use of concomitant drugs, respectively. To address these challenges, a series of comprehensive pharmaceutical interventions was introduced. By identifying individual risk factors, closely monitoring drug-food interactions, and providing tailor-made nutritional and medication counseling, the clinic was able to offer more personalized support. Furthermore, maintaining regular INR check-ups and collaborating closely with physicians for precise dose adjustments led to a remarkable improvement; the proportion of patients achieving their target INR levels or Time in Therapeutic Range (TTR) rose significantly from 42.35% in August 2024 to 65.58% by May 2025.

Ultimately, these outcomes demonstrate that continuous and well-structured pharmaceutical care, paired with practical dietary advice, is essential for helping patients maintain stable INR levels. Not only does this proactive approach lower the likelihood of severe bleeding or dangerous blood clots, but it also enhances medication safety and elevates the overall quality of life for individuals living with warfarin therapy.