Time in Therapeutic Range Significantly Impacts Survival and Adverse Events in Destination Therapy Patients

Objective: Patient self-management (PSM) is self-testing and altering the dose of their warfarin which allows for more frequent self-testing of warfarin levels, rapid results, timely dosage change, less dependency on the healthcare provider, and can be done anywhere. The objective of this study was to determine if PSM of warfarin is as safe and effective as healthcare provider dosing. Method: The setting for this study was a large cardiology practice that manages over 1000 patients on warfarin. Of these patients, 500 (50%) were using warfarin due to a valve replacement and 155 (16%) were engaged in self-testing. The final sample included 50 (32%) patients using self-testing who completed a 2-hour structured educational program on PSM of warfarin and practiced PSM for a 13-week period. Percentage of time the INR was maintained in therapeutic range, variance from the prescribed INR, and the adverse events of bleeding or thromboembolism were measured for 13 weeks pre-PSM and 13 weeks during PSM. Data were analyzed using t-test, correlation and Wilcoxson rank sum test. Results: There was no significant difference in pre-PSM time in therapeutic range compared with during PSM time in therapeutic range (p = .74). The mean INR variance from the prescribed INR range decreased significantly during PSM compared with pre-PSM, (p = .03), and when the INR did vary from the patient-specific prescribed range it tended to be in the high range but this did not reach significance (p = .67). These were desirable effects because this patient population is at high risk for embolic events. There was no significant increase in adverse events during PSM (p = .32). Conclusion: PSM of Warfarin was found to be as safe and effective as provider management. Moreover, PSM resulted in tighter control of INR variance compared with provider dosing. These results support the use of PSM of warfarin for eligible patients. Furthermore the model of PSM used in this study elicited patient engagement in behaviors that reduced the impact of their disease and decreased the burden of care on the healthcare provider.

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Use of SAMe-TT₂R₂ Score to Predict the Quality of Anticoagulation Control in Patients with Atrial Fibrillation Receiving Warfarin in Thailand

Journal of the Medical Association of Thailand ◽

10.35755/jmedassocthai.2020.06.10827 ◽

2020 ◽

Vol 103 (6) ◽

pp. 548-552

Keyword(s):

Atrial Fibrillation ◽

Therapeutic Range ◽

Statistical Significance ◽

Discrimination Performance ◽

Poor Quality ◽

Chi Square ◽

Exact Test ◽

Time In Therapeutic Range ◽

Anticoagulation Control

Objective: To predict the quality of anticoagulation control in patients with atrial fibrillation (AF) receiving warfarin in Thailand. Materials and Methods: The present study retrospectively recruited Thai AF patients receiving warfarin for three months or longer between June 2012 and December 2017 in Central Chest Institute of Thailand. The patients were classified into those with SAMe-TT₂R₂ of 2 or less, and 3 or more. The Chi-square test or Fisher’s exact test was used to compare the proportion of the patients with poor time in therapeutic range (TTR) between the two groups of SAMe-TT₂R₂ score. The discrimination performance of SAMe-TT₂R₂ score was demonstrated with c-statistics. Results: Ninety AF patients were enrolled. An average age was 69.89±10.04 years. Most patients were persistent AF. An average CHA₂DS₂-VASc, SAMe-TT₂R₂, and HAS-BLED score were 3.68±1.51, 3.26±0.88, and 1.98±0.85, respectively. The present study showed the increased proportion of AF patients with poor TTR with higher SAMe-TT₂R₂ score. The AF patients with SAMe-TT₂R₂ score of 3 or more had a larger proportion of patients with poor TTR than those with SAMe-TT₂R₂ score of 2 or less with statistical significance when TTR was below 70% (p=0.03) and 65% (p=0.04), respectively. The discrimination performance of SAMe-TT₂R₂ score was demonstrated with c-statistics of 0.60, 0.59, and 0.55 when TTR was below 70%, 65% and 60%, respectively. Conclusion: Thai AF patients receiving warfarin had a larger proportion of patients with poor TTR when the SAMe-TT₂R₂ score was higher. The score of 3 or more could predict poor quality of anticoagulation control in those patients. Keywords: Time in therapeutic range, Poor quality of anticoagulation control, Warfarin, SAMe-TT₂R₂, Labile INR

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