Neurocognitive functioning of patients with sickle cell disease in low- and middle-income countries

Sickle cell disease (SCD) is a monogenic blood disorder that affects the production of hemoglobin. Patients with SCD display slowed neurocognitive development resulting from a combination of cerebrovascular complications and sociodemographic factors. In low- and middle-income countries (LMICs), patients have limited access to neurocognitive surveillance. We sought to evaluate the neurocognitive impact of SCD in patients living in LMICs, establish which neurocognitive assessment measures are commonly used in this setting, and determine how these measures are contextually adapted. To answer these questions, we used an exhaustive literature search to systematically collect abstracts. Studies that focused on participants with SCD of any genotype and included a measure of cognitive/academic outcomes were included, whereas commentaries and editorials were excluded. A total of 1831 abstracts were screened, with 39 abstracts selected for full-text review and 21 articles used for data extraction. Most studies were conducted in Africa, Middle Eastern countries, and Brazil. Common measures included the Wechsler Intelligence Scale for Children or Adults. In 8 studies that included a measure of overall intelligence for patients with SCD and a control group, patients with SCD showed lower performance (z = -3.44, P = .0006) than controls. Information regarding cultural or language adaptations of neurocognitive measures was rarely reported, suggesting that neurocognitive measures are routinely used outside of the linguistic and cultural parameters for which they were developed. Further research is needed to validate the neurocognitive measures used in LMICs for patients with SCD.