Epidemiology of venous thromboembolism in Africa: a systematic review

Abstract

Background Venous thromboembolism (VTE) is among the three leading causes of cardiovascular disease worldwide. Despite its high burden, there has been no previous study summarizing the epidemiology of VTE in African populations. Hence, we conducted this systematic review to determine the prevalence, incidence and mortality associated with VTE, and to evaluate the use of VTE prophylaxis in Africa. Methods We searched PubMed, Scopus and African Journals Online to identify articles published on VTE in Africa from inception to November 19, 2016, without language restriction. The reference list of eligible articles were further scrutinized to identify potential additional studies. Results Overall, we included 21 studies. The great majority of the studies yielded a moderate risk of bias. The prevalence of deep vein thrombosis (DVT) varied between 2.4% and 9.6% in postoperative patients, and between 380 and 448 per 100 000 births per year in pregnant and postpartum women. The prevalence of pulmonary embolism (PE) in medical patients varied between 0.14% and 61.5%, with a mortality rate of PE between 40% and 69.5%. The case-fatality rate after surgery was 60%. Overall, 31.7-75% of the patients were at risk of VTE, and between 34.2% and 96.5% of these received VTE prophylaxis. Conclusion The prevalence of VTE and associated mortality are high following surgery, and in pregnant and postpartum women in Africa. At least one-quarter of patients who are at risk for VTE in Africa are not receiving prophylaxis. These results are generated from studies with small sample size, highlighting an urgent need for well-designed studies with larger sample size to evaluate the true burden of VTE in Africa.