Rivaroxaban has emerged as a potential alternative to warfarin for the prevention of thromboembolism in patients with atrial fibrillation (AF). However, there has been concern for the risk of major bleeding, especially in Asian patients. We investigated the efficacy and safety of rivaroxaban compared to warfarin in Korean real world practice. A total of 2,208 consecutive non-valvular AF patients were divided into the Warfarin group (n=990) and the Rivaroxaban group (n=1218). Propensity matched 1-year clinical outcomes were compared (Warfarin, n=804; Rivaroxaban, n=804). The efficacy outcome was defined as stroke/systemic embolism (SE). The safety outcome was major bleeding. The primary net clinical benefit (NCB) was defined as the composite of stroke/SE, major bleeding, and all-cause mortality. Secondary, NCB was defined as the composite of stroke, SE, and major bleeding. Rivaroxaban had the similar efficacy in terms of thromboembolic event prevention [hazard ratio (HR) 0.69, 95% confidence interval (CI) 0.37–1.32, p=0.266] compared to warfarin. Rivaroxaban significantly lowered the risk of major bleeding [HR 0.41, 95% CI 0.22–0.76, p=0.004]. Primary NCB was significantly low in the rivaroxaban group [HR 0.54, 95% CI 0.36–0.81, p=0.003]. Secondary NCB was also low in the rivaroxaban group [HR 0.62, 95% CI 0.40–0.99, p=0.041]. Both rivaroxaban 15 mg and 20 mg groups had similar efficacy and significantly lower risks of major bleeding as well as primary and secondary NCB compared to the warfarin group. In patients with non-valvular AF, rivaroxaban had a similar efficacy to warfarin in Korean real world practice. However, rivaroxaban had better safety and net clinical outcomes compared to warfarin.

Hemochromatosis is an inherited genetic disorder of iron metabolism which can also occur as a secondary result of iron-overload. It leads to organ damage such as cardiomyopathy, liver cirrhosis, hypogonadism, and diabetes. This paper discusses a case of secondary hemochromatosis associated with repeated transfusions, presenting as asymptomatic hypoparathyroidism and subclinical hypothyroidism with multiple organ involvement. The 29-year-old female, who had severe aplastic anemia, received multiple transfusions totaling approximately 1,400 units of red blood cells over 15 years. During her routine laboratory examination, hypocalcemia was detected with decreased intact parathyroid hormone and increased thyroid stimulating hormone. Serum ferritin, iron, and total iron binding capacity had increased to 27,583.03 ng/mL, 291 µg/dL, and 389 µg/dL, respectively. She had unusually bronze skin and computed tomography revealed iron deposition in the thyroid, liver, and heart. Multiorgan involvement as seen in this case is rare in hemochromatosis associated with secondary transfusions. To the best of the author's knowledge, this is the first case report in Korea of hypoparathyroidism and subclinical hypothyroidism due to iron deposition in the parathyroid and thyroid gland.

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Background and Objectives: Although anticoagulation with warfarin is recommended as an international normalized ratio (INR) of prothrombin time between 2.0 and 3.0 and mean time in the therapeutic range (TTR) ≥70%, little has been proven that universal criteria might be suitable in Korean atrial fibrillation (AF) patients. Methods: We analyzed 710 patients with non-valvular AF who took warfarin. INR value and clinical outcomes were assessed during 2-year follow-up. Intensity of anticoagulation was assessed as mean INR value and TTR according to target INR range. Primary net-clinical outcome was defined as the composite of new-onset stroke and major bleeding. Secondary netclinical outcome was defined as the composite of new-onset stroke, major bleeding and death. Results: Thromboembolism was significantly decreased when mean INR was over 1.6. Major bleeding was significantly decreased when TTR was over 70% and mean INR was less than 2.6. Mean INR 1.6-2.6 significantly reduced thromboembolism (adjusted hazard ratio [HR], 0.40; 95% confidence interval [CI], 0.19-0.85), major bleeding (HR, 0.43; 95% CI, 0.23-0.81), primary (HR, 0.50; 95% CI, 0.29-0.84) and secondary (HR, 0.45; 95% CI, 0.28-0.74) net-clinical outcomes, whereas mean INR 2.0-3.0 did not. Simultaneous satisfaction of mean INR 1.6-2.6 and TTR ≥70% was associated with significant risk reduction of major bleeding, primary and secondary net-clinical outcomes. Conclusions: Mean INR 1.6-2.6 was better than mean INR 2.0-3.0 for the prevention of thromboembolism and major bleeding. However, INR 1.6-2.6 and TTR ≥70% had similar clinical outcomes to INR 2.0-3.0 and TTR ≥70% in Korean patients with non-valvular AF.

Little is known as to why elevated red cell distribution width (RDW) is associated with adverse clinical outcomes in patients with atrial fibrillation (AF). We hypothesized that RDW value might predict the intensity of anticoagulation, resulting in higher adverse events in patients with AF taking warfarin. We analyzed 657 patients with non-valuvular AF who took warfarin. The intensity of anticoagulation was assessed as mean time in the therapeutic range (TTR) and defined TTR ≥60% as an optimal intensity. The primary end-point was the composite of stroke/systemic embolism and major bleeding. The secondary end-point was the composite of stroke/systemic embolism, major bleeding and death. The relationship between the baseline RDW with TTR and clinical outcomes was assessed using categorical variables as quartiles or dichotomous variables. The mean value of TTR decreased as an increment of the RDW (45.2% vs. 44.7% vs. 40.8% vs. 35.2%, p<0.001). Primary and secondary end-points were significantly increased when TTR was less than 60% and RDW was more than 13.6%. Ratio of patients achieving optimal anticoagulation were significantly decreased as an increment of RDW. A RDW of ≥13.6% was a significant predictor for poor anticoagulation control (adjusted Odds ratio [OR] 0.43, 95% confidence interval [CI] 0.23–0.82), stroke (adjusted hazard ratio [HR] 3.86, 95% CI 1.11–13.40), primary (adjusted HR 1.88, 95% CI 1.12–3.16) and secondary end-point (adjusted HR 2.46, 95% CI 1.26–4.81). RDW was negatively associated with TTR in patients with AF. Therefore, RDW might be a useful marker for the prediction of anticoagulation response and clinical outcomes in patients with AF.