Impact of Potential Antithrombotic Undertreatment on Clinical Outcomes in Patients with Atrial Fibrillation in Gondar University Hospital: a Retrospective Cohort Study

Abstract

ABSTRACT Introduction: Atrial fibrillation is a major risk factor for stroke as it increases the incidence of stroke nearly fivefold. Antithrombotic treatment is recommended for the prevention of stroke in AF patients. However, majorly due to fear of risk of bleeding, adherence to recommendations is not observed. Objectives: The aim of this study was to investigate the impact of potential antithrombotic undertreatment, on the clinical outcomes among adult atrial fibrillation patients attending Gondar University Hospital. Methods: The study was conducted from January 7, 2017 to April 30 2017 at Gondar University Hospital. A retrospective cohort study was conducted on medical records of patients with atrial fibrillation attending the medical inpatient ward and chronic ambulatory clinic of Gondar University Hospital between November 2012 and September 2016. Descriptive statistics were used to summarize sociodemographic and other baseline information. Patients receiving guidelineadherent

antithrombotic treatment and those on potential undertreatment, were followed for development of clinical events (ischemic stroke and/or all-cause mortality). Kaplan-Meier and a log-rank tests were used to plot the survival analysis curve. A stepwise cox hazard regression was used to determine the predictors of guideline-adherent antithrombotic therapy. Results: The final analysis included 159 atrial fibrillation patients with a median age of 60 years. Of these, nearly two third (64.78%) of patients were receiving potential undertreatment for antithrombotic medications. Upon multivariate analysis, history of ischemic stroke/transient ischemic attack was associated with lower incidence of antithrombotic potential undertreatment. A significant increase (AHR: 8.194, 95% CI: 2.911-23.066) in the incidence of ischemic stroke and/or all-cause mortality was observed in patients with potential undertreatment. Even if increased age was associated with a statistically significant increase risk for ischemic stroke and/or all-cause mortality, it was very modest (AHR: 1.035, 95% CI: 1.004-1.067]. On the other hand only history of ischemic stroke/transient ischemic attack (AHR: 0.038, 95% CI: 0.002-0.596) was associated with a decrease in the risk of ischemic stroke and/or all-cause mortality. Conclusion: Adherence to antithrombotic guideline recommendations was found to be crucial in reducing the incidence of ischemic stroke and/or all-cause mortality in patients with atrial fibrillation without increasing the risk of bleeding. However, potential undertreatment to antithrombotic medications was found to be high and was associated with poorer outcomes in terms of ischemic stroke and/or all-cause mortality. Key Words: Atrial Fibrillation, Ischemic Stroke, Antithrombotic Treatment, Gondar University Hospital, Ethiopia