Anticoagulation control among patients with nonvalvular atrial fibrillation: A single tertiary cardiac center experience

Abstract

There is a limited knowledge about the predictors of anticoagulation control in patients with nonvalvular atrial fibrillation (NVAF). Furthermore, few reports addressed the role of time in therapeutic range (TTR) that could reflect the safety and efficacy of anticoagulation therapy. We aimed to assess factors that affect the quality of anticoagulation therapy utilizing TTR in patients with NVAF. A retrospective observational study was conducted for patients with NVAF who were maintained on warfarin >6 months at a tertiary cardiac care hospital. Patients were categorized according to the TTR status (≥65% vs. <65%). A total of 241 eligible patients were identified. A high-quality anticoagulation based on TTR values ≥65% was found in 157 (65.1%) patients; the remaining (34.9%) patients represented the low-quality anticoagulation group (TTR <65%). Demographics and clinical characteristics were comparable in the two TTR groups. Both groups were comparable in terms of warfarin dose and medications use. When compared to patients with high-quality anticoagulation, patients in the low-quality anticoagulation group were more likely to seek outpatient warfarin clinic visits more frequently (22.3 ± 5.5 vs. 18 ± 4.4, P = 0.001) and to have higher rate of polypharmacy (57.1% vs. 42%, P = 0.03). Of note, patients in both groups had similar major bleeding events (P = 0.41). After adjusting for age and sex, polypharmacy use was a predictor of poor coagulation control (odds ratio = 1.89, 95% confidence interval: 1.03–3.33; P = 0.03). In NVAF patients, TTR is generally high in our cohort. Patients with polypharmacy and frequent clinic visits have lower TTR. High-quality oral anticoagulation could be achieved through optimizing TTR without a significant risk of major bleeding.

Evaluation of the Validity of SAMe-TT2R2 Score in a Cohort of Venous Thromboembolism Patients Treated With Warfarin

“…Of note, the relatively high TTR (76.7 [±18.6]) reported in this study is in line with previous data from Qatar. 33 , 34 In one study, mean TTR in pharmacist managed anticoagulation clinic was remarkably high and significantly higher than that observed in a historical cohort from a doctor-based clinic (81.8% vs 69.8%, P < .001). 33 Another study revealed an overall patients’ median TTR of 70% (range 19-100) with a numerically higher mean TTR in Arabs than in Asian patients (71% ±15% vs 67% ±17%, P = .15).…”

“… 33 Another study revealed an overall patients’ median TTR of 70% (range 19-100) with a numerically higher mean TTR in Arabs than in Asian patients (71% ±15% vs 67% ±17%, P = .15). 34 …”

“…33 Another study revealed an overall patients' median TTR of 70% (range 19-100) with a numerically higher mean TTR in Arabs than in Asian patients (71% +15% vs 67% +17%, P ¼ .15). 34 Excluding patients with reported poor compliance to warfarin and/or clinic visits may have also contributed to this high TTR. However, data about the exact number of such excluded patients in unavailable.…”

Anticoagulation Control in Different Ethnic Groups Receiving Vitamin K Antagonist for Stroke Prevention in Atrial Fibrillation

“…As shown in Table 2 , most of the studies used TTR ≥ 70 as their cut-off point indicating good anticoagulant control in AF patients. Moreover, there were also other studies ( 30 , 32 ) that used TTR ≥ 60 and TTR ≥ 65 as their cut-off point to indicate good anticoagulant control among their AF patients.…”

“…Among the 18 studies ( 9 , 26 – 42 ) from the findings, eight studies ( 27 , 28 , 32 , 33 , 37 – 39 , 42 ) stated TTR among each specific ethnic groups in their population and the other 10 studies ( 9 , 29 – 31 , 34 – 37 , 40 , 41 ) only mentioned the TTR in their overall population (whites, Asians). So far, in Malaysia, there is no study being conducted that focused on TTR among different ethnic groups.…”