PROPOSAL FOR THE INCLUSION OF LOW MOLECULAR WEIGHT HEPARINS FOR THE PREVENTION OF VENOUS THROMBOEMBOLISM IN HOSPITALIZED PATIENTS IN THE WHO MODEL LIST OF ESSENTIAL MEDICINES

Venous thromboembolism (VTE) is one of the leading causes of morbidity and mortality in hospitalized patients and pulmonary embolism is responsible for 10% of overall deaths. Because symptoms of deep vein thrombosis and pulmonary embolism are non-specific, a timely diagnosis remains difficult and screening tests for VTE are not cost-effective. Thus, careful selection of patients at increased risk and application of adequate prophylactic strategies is necessary to reduce the burden of disease. There is a large amount of evidence showing the efficacy of prophylactic strategies to prevent VTE in at-risk hospitalized patients. Pharmacologic prophylaxis with either low-dose unfractionated heparin (LDUH) or low molecular weight heparin (LMWH) has been shown to reduce the risk of pulmonary embolism in general surgical patients by 75%. Because of their greater ease of use (single daily dose) and their improved safety profile (the frequency of heparin induced thrombocytopenia is three-fold lower with LMWH than with unfractionated heparin), LMWH has widely become the management of choice for prophylaxis of VTE in this setting. In patients undergoing major orthopedic surgery, LMWH has been shown to be the most effective agent before the arrival of the direct oral anticoagulant drugs (DOACs) by producing an approximately 70% risk reduction in VTE and is currently recommended as the treatment of choice in this setting (see below). It was estimated that approximately two out of three patients undergoing surgical procedures should be deemed eligible to receive antithrombotic prophylaxis. Unfortunately, the results of a large observational study carried out in several countries throughout the world (ENDORSE) reported that only about 60% of at-risk surgical patients actually receive adequate prophylactic strategies. However, this rate widely varied among countries, being highest in western European countries and lowest in low and middle income Asian countries. In countries like Bangladesh, India, Pakistan, and Thailand, prescription rates ranged between 0.2% and 16.3%. These rates were higher in Northern African countries (Egypt, Tunisia, Algeria) while no information was available for Central African countries. Insufficient availability of drugs, but also insufficient awareness of post-surgical VTE as a major clinical issue remain the main drivers for this major gap between evidences and clinical practice. For example, the incidence of post-surgical venous thrombosis has traditionally been thought to be low in Asian ethnic populations. However, recent studies have challenged this common view showing that this incidence is similar to that reported in Western countries. For these reasons, we believe that improving access to drugs with the highest effectiveness in the prevention of VTE in surgical patients has the potential to reduce the burden of disease and thrombosis related costs also in low and middle income countries. However, this improvement can only be achieved in conjunction with an improved awareness of this life-threatening disease.