Warfarin Adherence and Its Associated Factors in Thai Older Adults with Atrial Fibrillation

Introduction: Older people mostly found unable to adhere with warfarin treatment guidelines. The health service system is challenged in order to improve medication adherence in older population under limited health resources. The purpose of this study was to explore health systems factors on warfarin adherence in older population, particularly in resources constraint setting.
Methods: This study was a cross-sectional predictive study that enrolled older people who experienced atrial fibrillation (AF) and treated by warfarin, aged 60 years and over, and followed up at the warfarin clinic.
Results: A total of 197 participants with the mean age of 72.03 years (SD = 8.84) was recruited. Almost of them (85.8%) reported adhered to warfarin prescription. More than a half (60.5%) were able to report their targeted INR. Participants who stayed with the family had 5.54 times (95% CI 1.79– 19.33), took regular daily dose warfarin had 5.07 times (95% CI 1.05– 24.49), perceived targeted INR had 2.94 times (95% CI 1.04– 8.29), and received family support had 1.33 times (95% CI 1.11– 1.60) increased odds of warfarin adherence than those who did not. Participants who perceived a barrier to taking medication had 0.93 times decreased odds of warfarin adherence than those who did not (95% CI 0.86– 0.99).
Conclusion: Healthcare system should encourage family to support the older population with AF in order to increase warfarin adherence. Future research should develop intervention combining family support to promote warfarin adherence.

Keywords: adherence, atrial fibrillation, INR, older population, warfarin