Alihan Oral1, Semih Başçı2, Osman Köstek3, Mehmet Uzunlulu4

1Department of Internal Medicine, Demiroğlu Bilim University, Faculty of Medicine, Istanbul, Turkey
2Department of Hematology, University of Health Sciences, Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital, Ankara, Turkey
3Department of Internal Medicine, Division of Oncology, Trakya University, Faculty of Medicine, Edirne, Turkey
4Department of Internal Medicine, Medeniyet University, Goztepe Training and Research Hospital, Istanbul, Turkey

Keywords: Bleeding, clinical characteristics, risk factors, warfarin overdose


Objectives: This study aims to investigate the relationship between overdose and patient characteristics by specifying characteristics such as age, gender, comorbidity, laboratory, diet, and treatment in patients hospitalized due to warfarin overdose.

Materials and methods: A total of 167 (91 males, 76 females, mean age 77±12 years; range 26 to 94 years) consecutive patients hospitalized at the Göztepe Training and Research Hospital Internal Medicine Clinic between May 2015 and May 2016 with International Normalized Ratio (INR) >3.50 were included in the study. Demographic data, comorbidity states, warfarin indications, thromboembolic risk scoring (CHA2DS2-VASc), bleeding risk score (HASBLED), laboratory parameters and previous hospitalizations for the same cause, current medications, diet, and bleeding origin of patients were documented.

Results: The most common warfarin indication was atrial fibrillation and the most common comorbidity was hypertension. Mean warfarin dosage was 30.8±8.7 mg/week. Mean CHADS2-VASC was 4.2±1.2, mean HASBLED was 3.6±0.9, mean INR was 8.0±3.6, and mean Time in Therapeutic Range (TTR) was 28.7±22.6%. The most common drug with warfarin interaction were proton pump inhibitor. A total of 68.9% of patients were found to be using over five medications and %21.6 of patients consuming food with possible warfarin interaction. Rate of rehospitalization due to warfarin overdose was %28.7. Bleeding frequency was %58.1. Mean INR and HASBLED was higher and mean TTR (p=0.04) was lower in patients with bleeding compared to non-bleeding patients (p=0.007, p<0.001). Male gender (p=0.007) and high HASBLED score (p<0.001) were independent risk factors for bleeding.

Conclusion: In inpatients hospitalized due to warfarin overdose, medications, and consumption of foods interacting with warfarin were found to be frequent; almost one third of patient were rehospitalized due to warfarin overdose, and high HASBLED score, and low TTR was associated with higher bleeding risk.

Conflict of Interest

The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

Financial Disclosure

The authors received no financial support for the research and/or authorship of this article.