Why the study?
VKAs remain primary anticoagulants for venous thromboembolism requiring regular monitoring, motivating evaluation of indications and factors associated with suboptimal anticoagulation control in northern Tanzania.
What is the level of anticoagulation control and what factors are associated with suboptimal control among patients on long-term Vitamin K antagonists in northern Tanzania?
What is the level of anticoagulation control and what factors are associated with suboptimal control among patients on long-term Vitamin K antagonists in northern Tanzania?
Anticoagulation control among patients on Vitamin K antagonists in northern Tanzania is extremely poor (TiTR 16%), driven by lack of health insurance, alcohol use, and infrequent monitoring.
Poor VKA control was associated with lack of insurance, alcohol use, and infrequent monitoring; hypothesis-generating for targeted interventions in low-resource settings.
Background Vitamin K antagonists (VKA) continue to be the principal anticoagulants for both the treatment and prevention of venous thromboembolism. The use of VKA often requires regular monitoring to avoid over-anticoagulation and prevent thromboembolic complications. The aim was to determine the indication for VKA use and factors associated with suboptimal anticoagulation control among patients in northern Tanzania. Methods This was a retrospective cohort study that examined the anticoagulation data of patients on long-term VKA from 1 st January 2020 to 31 st December 2022. Eligible participants were those on VKAs for at least 7 days and with at least 3 international normalized ratio (INR) results. The level of anticoagulation control was determined through the calculation of the time-in-therapeutic range (TiTR) using the Rosendaal and the percent of INR in therapeutic range methods. Results TiTR was found to be 17% using the direct method and 16% using the Rosendaal formula. 102 tests out of 365 were within the target range (28%). Absence of health insurance (aRR: 1.24, 95% CI: 1.06-1.44, P = .007), alcohol consumption (aRR: 1.37, 95% CI: 1.15-1.62, P < .001), and prolonged intervals between tests of 14 to 28 days (aRR: 1.34, 95% CI: 1.05-1.74, P = .018) showed association with INR being out of range. Conclusion Patients who achieved target therapeutic anticoagulation control were less than the acceptable 65%. Anticoagulation outcomes were better in patients with frequent INR monitoring and those with health insurance. Alcohol consumption carries a high risk of poor anticoagulation control. Further studies are needed to enforce better INR control.
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Gharib et al. (2025) studied this question.
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