Status of international normalized ratio control and treatment patterns in patients with nonvalvular atrial fibrillation taking vitamin K antagonist with or without antiplatelet therapy: Results from KORAFII registry

Abstract

Background Studies have shown that the concomitant use of a vitamin K antagonist (VKA) and an antiplatelet (APL) drug increased the bleeding risk and was less effective at preventing ischemic events. This study aimed to investigate the control status of international normalized ratio (INR) and the discontinuation rate of a VKA in patients taking VKA plus an APL drug compared with those taking a VKA alone. Methods Data were extracted from the KORean Atrial Fibrillation Investigation II registry, a multicenter noninterventional prospective observational study. Nonvalvular atrial fibrillation (NVAF) patients with CHADS2 scores ≥ 1 who newly started (within 3 months) a VKA were enrolled and followed up for 1 year. Results A total of 866 NVAF patients (mean age, 67.7 years; 60.3% men) without a bleeding history were divided into the VKA+APL (n = 229) and VKA alone (n = 637) groups. During follow‐up, mean INR level was lower in the VKA+APL group than in the VKA alone group (1.7 ± 0.8 vs 1.9 ± 0.9, P = 0.0005). INR levels were poorly controlled in both groups (66.1% and 64.7%, respectively). Patients in the VKA+APL group more frequently discontinued VKA than patients in the VKA alone group (28.8% vs 24.2%, P = 0.045). Major causes of VKA discontinuation were uncontrolled INR level and patient dissatisfaction or concerns. Conclusions The conditions of NVAF patients were inadequately controlled with VKA with or without an APL. These findings suggest that other antithrombotic treatment options are warranted in NVAF patients to achieve INR control.

Reasons for discontinuing oral anticoagulation therapy for atrial fibrillation: a systematic review

“…Of the 12 studies included in the review ( Table 2 ), most provided reasons related to the categories discontinuation due to patient’s choice, adverse events and other reasons ( Figure 2 ). Two reported discontinuation data from patient surveys and interviews [ 18 , 19 ], four reported data from clinical registries of patients with AF [ 21–23 ] and six reported data obtained from retrospective reviews of patients’ charts and hospital records [ 24–29 ]. Most studies provided information supporting inter-relationships between reasons ( Figure 3 ).…”

“…Both registries included a pre-specified list of reasons for discontinuations of treatment from which physicians may select one or multiple options. Two studies included interviews with patients, conducted in the UK [ 18 ] and Germany [ 19 ], and six employed retrospective chart reviews, one in Korea [ 24 ], one in the USA [ 24 ], two in Japan [ 26 , 27 ], one in Italy [ 28 ] and one in China [ 29 ]. The two Japanese studies were conducted separately but in the same department at Tokyo Womenʼs Medical University Hospital.…”

“…One study specifically assessed very old patients (≥80 years) [ 28 ] and another included patients who had AF and experienced transient ischaemic attack or ischaemic stroke (IS) [ 19 ]. Sample size varied substantially across studies, from 11 to 139 participants in the qualitative studies [ 18 , 19 ], from 300 to 900 in the retrospective chart review studies [ 24–29 ] and from 2,900 to 7,200 in the registry studies [ 20–23 ].…”

“…Two retrospective chart review studies reported data on patients treated with dabigatran, rivaroxaban, apixaban or warfarin [ 26 , 27 ], and one on patients treated with dabigatran, rivaroxaban, apixaban or edoxaban [ 25 ]. Three studies reported results for patients treated only with dabigatran [ 22 , 23 , 29 ] or only warfarin [ 18 , 21 , 30 ], one study reported on discontinuations from both warfarin and dabigatran [ 20 ], and two studies did not specify which oral anticoagulant drugs patients had received [ 19 , 24 ].…”

Physician's hand on the international normalized ratio level of vitamin K antagonist

“…Among all the comorbidities, cardiovascular disease that needs antiplatelet agents is even more challenging. In this issue, Park et al published an article telling how cardiovascular disease and antiplatelet therapy impact the use of VKA and the TTR …”