Risk Factors and Clinical Outcomes for Patients with Venous Thromboembolism in Kenya: Findings from the HEART Registry

Abstract

Background: Venous thromboembolism (VTE) encompassing deep vein thrombosis (DVT) and pulmonary embolism (PE) poses a significant burden despite advances in diagnostic and therapeutic options. The risk factors and clinical outcomes of VTE are dynamic, highlighting the need for more comprehensive studies, especially in sub-saharan Africa. This study aimed to identify risk factors and clinical outcomes in three major tertiary centers in Kenya. Methodology: The HEART Registry was developed in 2021 and recruited patients with VTE prospectively over three years from three facilities in Kenya. Patients’ demographics, risk factors for VTE, hospital course, and clinical outcomes over six months were obtained. Descriptive statistics were used to summarize the data, presenting the findings as frequencies, percentages, medians, and interquartile ranges. No pre-specified inferential or comparative analyses were planned, consistent with the descriptive registry design. Results: A total of 422 patients with VTE were prospectively enrolled. The median age was 46.5 years notably younger than typically reported in Western populations. DVT was the most common presentation (54%) followed by PE (38.4%). A substantial proportion of patients (49.5%) did not have any identifiable risk factors (unprovoked VTE). The most common acute-phase treatment was low molecular weight heparin (57.5%), followed by warfarin (28.6%). Direct oral anticoagulants recommended as first line therapy by current international guidelines were available but underutilized reflecting access constraints. Only 1.7% of participants received thrombolytic therapy. The median length of hospital stay was eight days. In the acute phase, 10.4% (n=31) of admitted participants died. At six-month follow-up, death occurred in an additional 39 patients. Conclusion: A substantial proportion of VTE patients in Kenya had no identifiable risk factors which is a pattern consistent with global data on unprovoked VTE. This highlights the need for caution in attributing VTE solely to preventable causes. VTE associated acute and six month mortality was high, driven predominantly by underlying comorbidities. Preventing VTE in acute medical conditions remains a major area of concern and future prospective studies are needed to identify novel population specific risk factors and optimize outcomes in this setting. Keywords: venous thrombosis, pulmonary embolism, deep vein thrombosis, anticoagulation, Kenya, sub-Saharan Africa, HEART Registry, risk factors, outcomes