Vitamin K antagonist such as warfarin reduces the risk of stroke in atrial fibrillation (AF) patients. Since warfarin has a narrow therapeutic index, its administration needs to be regularly monitored to avoid any adverse clinical outcomes such as stroke and bleeding. The quality of anticoagulation control with warfarin therapy can be measured by using time in therapeutic range (TTR). This review focuses on the prevalence of AF, quality of anticoagulation control (TTR) and adverse clinical outcome in AF patients within different ethnic groups receiving warfarin therapy for stroke prevention. A literature search was conducted in Embase and PubMed using keywords of "prevalence," "atrial fibrillation," "stroke prevention," "oral anticoagulants," "warfarin," "ethnicities," "race" "time in therapeutic range," "adverse clinical outcome," "stroke, bleeding." Articles published by 1st February 2020 were included. Forty-one studies were included in the final review consisting of AF prevalence (n = 14 studies), time in therapeutic range (n = 18 studies), adverse clinical outcome (n = 9 studies) within different ethnic groups. Findings indicate that higher prevalence of AF but better anticoagulation control among the Whites as compared to other ethnicities. Of note, non-whites had higher risk of strokes and bleeding outcomes while on warfarin therapy. Addressing disparities in prevention and healthcare resource allocation could potentially improve AF-related outcomes in minorities.
Background: Thrombotic conditions triggered by SARS-CoV-2 virus can result in high mortality, especially in pregnant women as they are already in a hypercoagulability state. This thereby leads to excessive inflammation that will increase the risk of thromboembolic (TE) complications. Objective: The aim of this study is to review the prevalence of thromboembolic complications such as deep venous thrombosis, pulmonary embolism, and intervillous thrombosis, and their preventive strategies among pregnant women infected with COVID-19. Method: The articles were retrieved from online databases PubMed and ScienceDirect published from February 2020 to April 2022. Findings: A total of 5249 participants including 5128 pregnant women and 121 placentas from 19 studies were identified for having TE complications after being infected with COVID-19. The types of TE complications that developed within pregnant women were disseminated intravascular coagulation (DIC) (n = 44, 0.86%), unmentioned thromboembolic complications (TE) (n = 14, 0.27%), intervillous thrombosis (IVT) (n = 9, 0.18%), pulmonary embolism (PE) (n = 6, 0.12%), COVID-19 associated coagulopathy (CAC) (n = 5, 0.10%), and deep venous thrombosis (DVT) (n = 2, 0.04%). Whereas the prevalence of TE complications reported from studies focusing on placenta were IVT (n = 27, 22.3%), subchorionic thrombus (SCT) (n = 9, 7.44%), and placental thrombosis (n = 5, 4.13%). Thromboprophylaxis agent used among pregnant women include low molecular weight heparin (LMWH) at prophylactic dose (n = 9). Conclusions: The prevalence of thromboembolic complications among pregnant women infected by COVID-19 is low with DIC being the most common form and placental thrombosis being the least common form of TE complications that occurred within pregnant women infected with COVID-19. Anticoagulation, in particular LMWH (variable dose), is frequently used to prevent TE complications.