Quality of Anticoagulation Management with Warfarin among Patients in Orotta National Referral Hospital, Asmara, Eritrea: A Retrospective Cross-Sectional Study

Document Type : Original Article


1 Bachelor in Pharmacy, National Medicine and Food Administration, Ministry of Health, Asmara, Eritrea.

2 Bachelor in Pharmacy, Ghindae Regional Referral Hospital, Ghindae, Eritrea.

3 Bachelor in Pharmacy, Mendefera Regional Referral Hospital, Mendefera, Eritrea.

4 Bachelor in Pharmacy, Azel Pharmaceutical Company, Keren, Eritrea.


To analyze the quality of anticoagulation management with warfarin in Orotta National Referral Hospital, Asmara, Eritrea.
 Materials and Methods:
A retrospective cross sectional study was conducted on patients aged 18 years and above who had received warfarin for Deep Vein Thrombosis and Valvular Heart Disease for at least 30 days. Data were collected by reviewing patients’ medical records. Time in Therapeutic Range (TTR) and International Normalized Ratio (INR) were used to analyze the quality and factors that affect the anticoagulation management.
Out of the 336 patients studied, 24.5% and 28.8% of patients, with Deep Vein Thrombosis (DVT) and Valvular Heart Diseases (VHD) respectively, had INR measurements within therapeutic range. The mean TTR was 25.1%, while the mean duration of INR monitoring for all patients was 40 days with a standard deviation of 43 days. The daily dose of warfarin was increased in 35.4% of participants following subtherapeutic INRs, and decreased in 50.6% following supratherapeutic INRs. No association was found between optimal TTR outcome and concomitantly used medications as well as comorbid conditions. However, the use of alternate dose regimen was found to be significantly associated with in-range (therapeutic) INR measurements.
The study concluded that the quality of anticoagulation management with warfarin among patients in Orotta National Referral Hospital was suboptimal. This was demonstrated by low mean TTR, longer INR monitoring frequency and unsatisfactory measures taken to adjust warfarin dose after occurrences of non-therapeutic INRs.


Main Subjects

  1. Wardrop D, Keeling D. The story of the discovery of heparin and warfarin. British journal of haematology. 2008;141(6):757-63.
  2. Ruff CT, Giugliano RP, Braunwald E, Hoffman EB, Deenadayalu N, Ezekowitz MD, et al. Comparison of the efficacy and safety of new oral anticoagulants with warfarin in patients with atrial fibrillation: a meta-analysis of randomised trials. Lancet (London, England). 2014; 383 (9921): 955-62.
  3. Mouton JP, Njuguna C, Kramer N, Stewart A, Mehta U, Blockman M, et al. Adverse Drug Reactions Causing Admission to Medical Wards: A Cross-Sectional Survey at 4 Hospitals in South Africa. Medicine. 2016;95(19):e3437.
  4. Crowther MA, Warkentin TE. Bleeding risk and the management of bleeding complications in patients undergoing anticoagulant therapy: focus on new anticoagulant agents. Blood. 2008; 111(10):4871-9.
  5. Gailani D, Reese EP, Jr. Anticoagulant-induced skin necrosis in a patient with hereditary deficiency of protein S. American journal of hematology. 1999;60(3):231-6.
  6. Weitz JI. Antiplatelet, Anticoagulant, and Fibrinolytic Drugs. In: Jameson. JL, Kasper. DL, Longo. DL, Fauci. AS, Hauser. SL, Loscalzo. J, editors. Harrison's Principles of Internal Medicine. I. 20th ed. New York: McGraw-Hill Education; 2018. p. 843-58.
  7. Aspinall SL, Zhao X, Handler SM, Stone RA, Kosmoski JC, Libby EA, et al. The quality of warfarin prescribing and monitoring in Veterans Affairs nursing homes. Journal of the American Geriatrics Society. 2010;58(8):1475-80.
  8. Ansell J, Hirsh J, Dalen J, Bussey H, Anderson D, Poller L, et al. Managing oral anticoagulant therapy. Chest. 2001;119(1 Suppl):22s-38s.
  9. Schmitt L, Speckman J, Ansell J. Quality assessment of anticoagulation dose management: comparative evaluation of measures of time-in-therapeutic range. Journal of thrombosis and thrombolysis. 2003;15(3):213-6.
  10. Fenta TG, Assefa T, Alemayehu B. Quality of anticoagulation management with warfarin among outpatients in a tertiary hospital in Addis Ababa, Ethiopia: a retrospective cross-sectional study. J BMC Health Services Research. 2017; 17(1): 1-7.
  11. Karuri SW. Quality of oral anticoagulation Management among patients on follow up at Kenyatta National Hospital: University of Nairobi; 2016.
  12. Dolan G, Smith LA, Collins S, Plumb JM. Effect of setting, monitoring intensity and patient experience on anticoagulation control: a systematic review and meta-analysis of the literature. Current medical research and opinion. 2008;24(5):1459-72.
  13. Hirsh J, Fuster V, Ansell J, Halperin JL. American Heart Association/American College of Cardiology Foundation guide to warfarin therapy. Circulation. 2003; 107(12): 1692-711.
  14. Holbrook A, Schulman S, Witt DM, Vandvik PO, Fish J, Kovacs MJ, et al. Evidence-based management of anticoagulant therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines.Chest. 2012;141(2 Suppl):e152S -e84S.
  15. Baker JW, Pierce KL, Ryals CA. INR goal attainment and oral anticoagulation knowledge of patients enrolled in an anticoagulation clinic in a Veterans Affairs medical center.Journal of mana- ged care pharmacy: JMCP.2011;17(2): 133-42.
  16. Garwood. CL, Dumo. P, Baringhaus. SN, Laban. KM. Quality of Anticoagulation Care in Patients Discharged from a Pharmacist-Managed Anticoagulation Clinic After Stabilization of Warfarin Therapy. Pharmacotherapy.2008;28 (1): 20–6.
  17. Mwita JC, Francis JM, Oyekunle AA, Gaenamong M, Goepamang M, Magafu M. Quality of Anticoagulation With Warfarin at a Tertiary Hospital in Botswana. Clinical and applied thrombosis/hemostasis : official journal of the International Academy of Clinical and Applied Thrombosis/ Hemostasis. 2018;24(4):596-601.
  18. Apostolakis S, Sullivan RM, Olshansky B, Lip GYH. Factors affecting quality of anticoagulation control among patients with atrial fibrillation on warfarin: the SAMe-TT₂R₂ score. Chest. 2013; 144(5):1555-63.
  19. Kizito M. Assessment of the patient factors impacting on oral anticoagulation therapy among adult outpatients at Kenyatta national hospital: University of Nairobi; 2015.