Vitamin K antagonists (VKA) is the primary anticoagulant in most settings of Sub-Saharan Africa. Understanding the quality of anticoagulation services in the continent is vital in optimising the intended benefits. This study assessed the quality of anticoagulation and associated factors among VKA-treated patients in nine SSA countries. We conducted a retrospective cohort study of randomly selected patients on anticoagulation from 20 clinics in Botswana, the Democratic Republic of Congo, Ethiopia, Gambia, Ghana, Mozambique, Nigeria, Tanzania, and South Africa. Eligible participants were those on VKAs for at least three months and with at least four international normalised ratios (INR) results in 2019–2021. We report the proportion of INR values in the therapeutic range, time-in-therapeutic range (TTR) using the Rosendaal method, and the proportion of patients with TTR ≥ 65% (optimal anticoagulation). The mean age was 51.1(16.1) years, and 64.2% were women. The most common indications for VKA included venous thromboembolism (29.6%), prosthetic valves (26.7%) and atrial fibrillation/flutter (30.1%). We analysed 6743 INR tests from 1011 participants, and of these, 48.5% were sub-therapeutic, 34.1% therapeutic, and 17.4% were supratherapeutic relative to disease-specific reference ranges. TTR was calculated for 660 patients using 4927 INR measurements. The median (interquartile range [IQR]) TTR was 35.8(15.9,57.2) %. Optimal anticoagulation control was evident in 19.2% of participants, varying from 2.7% in Tanzania to 23.1% in Ethiopia. The proportion of patients with TTR ≥ 65% was 15,4% for prosthetic heart valves, 21.1% for venous thromboembolism and 23.7% for atrial fibrillation or flutter. Countries with universal health coverage had higher odds of optimal anticoagulation control (adjusted odds ratio (aOR) 1.79, 95% confidence interval [CI], 1.15– 2.81, p = 0.01). Patients on VKAs for different therapeutic indications in SSA had suboptimal TTR. Universal health coverage increased the odds of achieving TTR by 79%. The evidence calls for more intensive warfarin management strategies in SSA, including providing VKA services without out-of-pocket payments.

维生素 K 拮抗剂 (VKA) 是撒哈拉以南非洲大多数地区的主要抗凝剂。了解非洲大陆抗凝服务的质量对于优化预期效益至关重要。这项研究评估了九个 SSA 国家接受 VKA 治疗的患者的抗凝质量和相关因素。我们对来自博茨瓦纳、刚果民主共和国、埃塞俄比亚、冈比亚、加纳、莫桑比克、尼日利亚、坦桑尼亚和南非 20 家诊所的随机选择的接受抗凝治疗的患者进行了一项回顾性队列研究。符合资格的参与者是那些服用 VKA 至少三个月且在 2019 年至 2021 年期间至少有四个国际标准化比率 (INR) 结果的参与者。我们使用 Rosendaal 方法报告了 INR 值在治疗范围内的比例、治疗时间范围 (TTR)，以及 TTR ≥ 65%（最佳抗凝）的患者比例。平均年龄为51.1（16.1）岁，其中64.2%为女性。VKA 最常见的适应症包括静脉血栓栓塞 (29.6%)、人工瓣膜 (26.7%) 和心房颤动/扑动 (30.1%)。我们分析了 1011 名参与者的 6743 项 INR 测试，其中相对于疾病特定参考范围，48.5% 为亚治疗，34.1% 为治疗，17.4% 为超治疗。使用 4927 个 INR 测量值计算了 660 名患者的 TTR。中位数（四分位距 [IQR]）TTR 为 35.8(15.9,57.2)%。19.2% 的参与者明显获得了最佳抗凝控制，这一比例从坦桑尼亚的 2.7% 到埃塞俄比亚的 23.1% 不等。人工心脏瓣膜 TTR ≥ 65% 的患者比例为 15.4%，静脉血栓栓塞患者为 21.1%，房颤或房扑患者为 23.7%。实现全民健康覆盖的国家获得最佳抗凝控制的几率较高（调整后优势比 (aOR) 1.79，95% 置信区间 [CI]，1.15–2.81，p = 0.01）。接受 VKA 治疗 SSA 不同治疗适应症的患者的 TTR 不理想。全民健康覆盖使实现 TTR 的几率提高了 79%。有证据表明，SSA 需要采取更强化的华法林管理策略，包括提供无需自付费用的 VKA 服务。