Lee SL, Ong TJ, Mazlan-Kepli W, Mageswaran A, Tan KH, Abd-Malek AM, Cronshaw R. Patients’ time in therapeutic range on warfarin among atrial fibrillation patients in Warfarin Medication Therapy Adherence Clinic. World J Cardiol 2021; 13(9): 483-492 [PMID: 34621493 DOI: 10.4330/wjc.v13.i9.483]
Corresponding Author of This Article
Siew Ling Lee, BPharm, Pharmacist, Department of Pharmacy, Hospital Serdang, Ministry of Health Malaysia, Jalan Puchong, Kajang 43000, Selangor, Malaysia. siewling.phc@gmail.com
Research Domain of This Article
Cardiac & Cardiovascular Systems
Article-Type of This Article
Retrospective Study
Open-Access Policy of This Article
This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
World J Cardiol. Sep 26, 2021; 13(9): 483-492 Published online Sep 26, 2021. doi: 10.4330/wjc.v13.i9.483
Patients’ time in therapeutic range on warfarin among atrial fibrillation patients in Warfarin Medication Therapy Adherence Clinic
Siew Ling Lee, Thien Jian Ong, Wardati Mazlan-Kepli, Annuysia Mageswaran, Kai Hsin Tan, Abdul-Muizz Abd-Malek, Robert Cronshaw
Siew Ling Lee, Thien Jian Ong, Wardati Mazlan-Kepli, Annuysia Mageswaran, Kai Hsin Tan, Department of Pharmacy, Hospital Serdang, Ministry of Health Malaysia, Kajang 43000, Selangor, Malaysia
Abdul-Muizz Abd-Malek, Department of Cardiology, Hospital Serdang, Ministry of Health Malaysia, Kajang 43000, Selangor, Malaysia
Robert Cronshaw, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G128QQ, United Kingdom
Author contributions: Mazlan-Kepli W contributed to the idea and study design; Siew-Ling L, Thien-Jian O, and Annuysia M contributed to and performed all data analyses and interpretation of results; Siew-Ling L and Thien-Jian O wrote the first manuscript; Wardati MK contributed to the interpretation of results and critically reviewed the final manuscript; All authors contributed to the review of an approved manuscript before submission.
Institutional review board statement: Ethical approval for this study was obtained from the Medical Research and Ethics Committee (MREC), Ministry of Health Malaysia (NMRR-19-839-46462).
Informed consent statement: Patients were not required to give informed consent to the study because the analysis used anonymous clinical data that were obtained after each patient agreed to treatment. Permission to use the patient data from this facility has been obtained from the Head of Department of Cardiology, Hospital Serdang.
Conflict-of-interest statement: The authors have no financial relationships to disclose.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Siew Ling Lee, BPharm, Pharmacist, Department of Pharmacy, Hospital Serdang, Ministry of Health Malaysia, Jalan Puchong, Kajang 43000, Selangor, Malaysia. siewling.phc@gmail.com
Received: March 10, 2021 Peer-review started: March 10, 2021 First decision: May 6, 2021 Revised: May 25, 2021 Accepted: July 26, 2021 Article in press: July 26, 2021 Published online: September 26, 2021
Abstract
BACKGROUND
The quality of warfarin therapy can be determined by the time in the therapeutic range (TTR) of international normalized ratio (INR). The estimated minimum TTR needed to achieve a benefit from warfarin therapy is ≥ 60%.
AIM
To determine TTR and the predictors of poor TTR among atrial fibrillation patients who receive warfarin therapy.
METHODS
A retrospective observational study was conducted at a cardiology referral center in Selangor, Malaysia. A total of 420 patients with atrial fibrillation and under follow-up at the pharmacist led Warfarin Medication Therapeutic Adherence Clinic between January 2014 and December 2018 were included. Patients’ clinical data, information related to warfarin therapy, and INR readings were traced through electronic Hospital Information system. A data collection form was used for data collection. The percentage of days when INR was within range was calculated using the Rosendaal method. The poor INR control category was defined as a TTR < 60%. Predictors for poor TTR were further determined by using logistic regression.
RESULTS
A total of 420 patients [54.0% male; mean age 65.7 (10.9) years] were included. The calculated mean and median TTR were 60.6% ± 20.6% and 64% (interquartile range 48%-75%), respectively. Of the included patients, 57.6% (n = 242) were in the good control category and 42.4% (n = 178) were in the poor control category. The annual calculated mean TTR between the year 2014 and 2018 ranged from 59.7% and 67.3%. A high HAS-BLED score of ≥ 3 was associated with poor TTR (adjusted odds ratio, 2.525; 95% confidence interval: 1.6-3.9, P < 0.001).
CONCLUSION
In our population, a high HAS-BLED score was associated with poor TTR. This could provide an important insight when initiating an oral anticoagulant for these patients. Patients with a high HAS-BLED score may obtain less benefit from warfarin therapy and should be considered for other available oral anticoagulants for maximum benefit.
Core Tip: This is a retrospective observational study to determine time in therapeutic range (TTR) and the predictors of poor TTR among patients with atrial fibrillation under follow-up at the Warfarin Medication Therapeutic Adherence Clinic of a tertiary cardiology referral center in Selangor, Malaysia. In this study cohort, we found that high HAS-BLED score (≥ 3) was a significant predictor of poor TTR.
