Implementation of point-of-care INR testing to improve effectiveness of anticoagulation clinic

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Oral Vitamin K antagonist (VKA) is still widely used for anticoagulation. Anticoagulation clinics are set up to monitor patients’ INR and adjust their VKA doses accordingly. Anticoagulation clinic in our centre introduced point-of-care (POC) INR testing in June 2021 to improve the effectiveness of the clinic. Purpose This audit was done to evaluate the effectiveness of anticoagulation since the introduction of the POC INR test into the clinic workflow. Methods This was a retrospective, cross-sectional, cohort audit study. The study period was from 1st June 2021 to 31st July 2022. List of patients who attended the clinic from 1st – 31st January 2022 was taken from the clinic log and their electronic medical records were reviewed for the study period. Only patients who have been established on VKA for at least 3 months were included in the audit. The data collected included their basic demographics, indication for VKA, any complications / death during the study period and if their VKA had been stopped and why and serial INRs from the POC INR test during the study period. The time in therapeutic range (TTR) is calculated by Rosendaal method and all the results analysed on Microsoft Excel. The audit standard for safe and effective anticoagulation was a TTR ≥ 70%. Results were compared to an audit done previously for the centre’s anticoagulation clinic done in 2020. Results 207 patients were included in this audit. Male patients accounted for 53.6% of the study population. Their ages ranged from 22 years to 102 years with a median age of 67 years. Majority of the patients were on VKA as stroke prevention for their atrial fibrillation (AF) (79.7%), followed by metallic valve replacement (13%). The median TTR for patients with AF had improved from 40.8% in 2020 to 51.05% in 2020-21 study period and this difference is significant (p = 0.017). Patients getting effective anticoagulation also improved from 23.26% in 2020 to 26.79% during this audit period. 13% of the study population developed complications on VKA in which 2.9% of patients developed gastrointestinal bleed and 1% developed intracranial haemorrhage. There were 4 fatalities, none were from gastrointestinal bleeding, intracranial haemorrhage or stroke. 10% of patients had their VKA changed to a novel oral anticoagulant (NOAC) as they were identified to have poor TTR during clinic review. Conclusions The introduction of POC INR test has proven to make significant improvement in patient’s median TTR for patients with AF. However, more efforts need to be made to further improve effectiveness of anticoagulation in our patients such as converting them to a NOAC if eligible or more thorough counselling and more frequent INR checks.