Comparison of risk factors for warfarin-associated bleeding

INTRODUCTION: Warfarin is the most commonly used oral agent for long-term anticoagulation. Nevertheless, bleeding is the most frequent side effect of warfarin, increasing mortality and morbidity and thereby restricting its use. Risk factors for bleeding include age, comorbid diseases, use of drugs that may interact with warfarin, and previous history of stroke or gastrointestinal bleeding. Using a questionnaire-based method, this study aimed to compare the risk of bleeding in two groups of warfarin users with and without a history of warfarin-related bleeding.
METHODS: A total of 201 patients, including 100 who had bleeding during warfarin use in our outpatient clinic and 101 patients who were followed up with the international normalization rate, were included in the study. Risk factors in warfarin-related bleeding were evaluated by the researcher with a questionnaire created as a result of the literature review. Data were statistically analyzed.
RESULTS: The prevalence of bleeding was 2.8 times higher in patients aged 65 years and older (confidence interval: 1.40-5.56) and 5.6 times higher in patients with comorbid diseases (confidence interval: 1.376-22.770). A history of stroke increased major bleeding 3.2 fold (confidence interval: 1.08-9.61). We also observed that lack of education might be a risk factor for warfarin-related bleeding.
DISCUSSION AND CONCLUSION: We believe that older patients under warfarin treatment should be informed according to their education status, and their medications and comorbid diseases should be monitored regularly by the same centers.