Sickle cell disease, sickle trait and the risk for venous thromboembolism: a systematic review and meta-analysis

Globally, sickle cell disease (SCD) is one of the most common haemoglobinopathy. Considered a public health problem, it leads to vessel occlusion, blood stasis and chronic activation of the coagulation system responsible for vaso-occlussive crises and venous thromboembolism (VTE) which may be fatal. Although contemporary observational studies suggest a relationship between SCD or sickle trait (SCT) and VTE, there is lack of a summary or meta-analysis data on this possible correlation. Hence, we propose to summarize the available evidence on the association between SCD, SCT and VTE including deep vein thrombosis (DVT) and pulmonary embolism (PE). We searched PubMed and Scopus to identify all cross-sectional, cohort and case-control studies reporting on the association between SCD or SCT and VTE, DVT or PE in adults or children from inception to April 25, 2017. For measuring association between SCD or SCT and VTE, DVT, or PE, a meta-analysis using the random-effects method was performed to pool weighted odds ratios (OR) of risk estimates. From 313 records initially identified from bibliographic databases, 10 studies were eligible and therefore included the meta-analysis. SCD patients had significantly higher risk for VTE (pooled OR 4.4, 95%CI 2.6-7.5,