Date of Award


Document Type


Degree Name

Master of Medicine (MMed)

First Supervisor/Advisor

Dr. Ahmed Sokwala

Second Supervisor/Advisor

Dr. Mzee Ngunga

Third Supervisor/Advisor

Dr. Jasmit Shah


Internal Medicine (East Africa)


Background: The past five years have seen an increase in the use of new oral anticoagulants (NOACS) for treatment and prophylaxis against venous thromboembolism. These agents are as effective as warfarin, with much fewer bleeding complications. The incidence of bleeding complications in patients with venous thromboembolism on NOACS (New oral anticoagulants) has not been widely studied in Africa's contemporary practice. The purpose of this study is to determine the rates of major bleeding and clinically relevant non-major bleeding (CRNM) associated with new oral anticoagulant use in daily contemporary clinical practice.

Methods: A retrospective review of adult patients diagnosed with venous thromboembolism and treated with NOACs at Aga Khan University Hospital (AKUHN) was conducted from January 2014 to December 2019. They were followed up from the time of commencement of oral anticoagulation to completion of therapy, first clinically relevant non-major bleeding (CRNM) or major bleed, or end of the study. Data on minor bleeding was also obtained. Clinical and demographic data were obtained through the medical records. Data on bleeding was obtained from the hospital database and through telephone interviews. Unadjusted rates of a first major bleeding event or CRNM bleeding were calculated as the number of bleeding events per 100 person-years.

Results: Two hundred forty-three patients with venous thromboembolism were recruited. Two hundred and twenty-two (91.4%) were initiated on rivaroxaban, 12 (4.9%) on dabigatran, 9 (3.7%) on apixaban with a median follow-up of 213 (IQR: 119, 477) days. The median age of the patients was 57(IQR: 45, 71) years. A total of 64 bleeding events were identified in 50 (20.6%) patients. Overall, the incidence rate for bleeding events was 17.24 per 100 patient-years. The incidence rate of major bleeding was 3.79 per 100 person-years. Gastrointestinal bleeding was the most common major bleeding site. There were more females with bleeding events (70.7%) compared to males. Anemia and use of aspirin and other antiplatelets were associated with a higher incidence of major and CRNM bleeding.

Conclusions: Most of these bleedings were minor, with the gastrointestinal system being the most common source of major bleeding and menorrhagia being the commonest cause of bleeding. Anemia and the use of aspirin were associated with a higher incidence of major bleeding.