Anticoagulation with Warfarin: Roles of Adherence, Social Support and Illness Perception

Abstract

Objectives: This study was aimed to determine (1) the associations between adherence to warfarin, social support, perception of illness, and demographic factors on the quality of international normalized ratios (INRs); as well as (2) the relationship between the patients' scores in the Malaysian medication adherence scale (MALMAS) and their current INRs.

Method: This cross-sectional survey was conducted from November 2017 to January 2018 at the warfarin clinic of Jerantut Hospital, Malaysia.

Results: Some 58 participants were recruited, of whom 70.7% were diagnosed with atrial fibrillation (AF). Overall, 87.9% of the participants claimed adherence to their warfarin regimens. Patients with good-quality INR therapy were significantly older, had a higher median income and longer appointment durations. In terms of illness perception (IP), participants with good-quality INR therapyhad significantly lower scores in the identity, personal control, and consequence domains. Overall, the total scores for IP were significantly lower in the good-quality INR therapy. Meanwhile, the MALMAS scores were significantly lower in patients with sub-therapeutic current INR. However, there were no associations between warfarin adherence and perceived social support with current TTR.

Conclusion: Monitoring of demographic factors and IP's domains is vital since they were associated with quality of INR therapy. Meanwhile, the occurrence of sub-therapeutic current INR should raise suspicion of poor adherence in these patients. Overall, IP and MALMAS are useful tools that should be integrated into the patient care protocols.

Keywords: Warfarin; adherence; illness perception; social support; time in therapeutic range.