Indications and quality of care of warfarin at King Abdulaziz Hospital, Al Ahsa

Abstract

Introduction: The anticoagulation effect of warfarin is monitored through two laboratory tests: Prothrombin Time (PT) and International Normalised Ratio (INR). The quality of warfarin control in patients is assessed by calculating the Time in Therapeutic Range (TTR) using INR values. However, there are only a few studies in Saudi Arabia that have investigated INR control in patients receiving warfarin.

Methods: Biographical data, indications for anticoagulation, and INR values were extracted from electronic medical records of patients on warfarin therapy between November 1, 2020, and October 31, 2021. The TTR for each patient was calculated using the Rosendaal method.

Results: A total of 88 patients were included in this study, comprising 29 males and 59 females. The indications for anticoagulation were categorised into four groups: ‘Mechanical Valve’ (28 patients), ‘Atrial Fibrillation’ (14 patients), ‘Mechanical Valve + Atrial Fibrillation’ (12 patients), and ‘Other Indications’ including haematological disorders (34 patients). The overall median TTR for the cohort was 58.73%. Patients with ‘Mechanical Valves’ had a median TTR of 62.50%, those with ‘Atrial Fibrillation’ had a median TTR of 50.18%, patients with ‘Mechanical Valve + Atrial Fibrillation’ had a median TTR of 54.61%, and patients with ‘Other Indications’ had a median TTR of 55.11%. The differences in TTR between these groups were not statistically significant (p = 0.101).

Conclusion: The INR control for patients taking warfarin was suboptimal, with a median TTR below the recommended threshold of 60%. This underscores the need for further studies to explore and improve the management of warfarin in patients.