The Centers for Disease Control and Prevention has classified sickle cell disease (SCD) as a condition that may put patients at increased risk of severe illness from COVID-19. Patients with SCD often have chronic inflammation, immunocompromise, and low oxygen saturation. Severe cases of COVID-19 infection can result in a cytokine storm that causes damage to organs, especially the lungs.
Therefore, it is important to understand whether patients with SCD are more susceptible to COVID-19 or whether they experience a more severe clinical course. A survey of published reports and international database of this patient population that recently appeared in Pediatric Blood and Cancer showed that COVID-19 was relatively mild among pediatric patients with SCD, moderate among most adults SCD, and more likely to be severe in older adults with SCD. The review also found support for the possible benefits of simple/exchange transfusion and hydroxyurea therapy in patients with both SCD and COVID-19.
The authors, led by Babak Sayad, MD, MPH, of the Infectious Diseases Research Center at Kermanshah University of Medical Sciences in Iran, conducted a literature review in PubMed, Web of Science, and Scopus to identify reports of COVID-19 among patients with SCD. They identified 27 published papers. The researchers analyzed data on mean age, death rate due to COVID-19, admission to the intensive care unit (ICU), hospitalization, SCD genotype, fetal hemoglobin (HbF) level, hydroxyurea (HU) therapy, transfusion during hospitalization, and history of comorbidities.
The researchers found that COVID-19 outcomes were good among children with SCD, but the rate of ICU admission was high. In adults with SCD, COVID-19 outcomes were variable, ranging from mild to severe. Older adults with SCD and pre-existing multiple organ damage were at highest risk of morbidity and mortality from COVID-19. The analyses did not find that hemoglobin genotype or gender affected COVID-19 disease severity. However, COVID-19 among patients with SCD was associated with cytokine storm and hypercoagulability.
According to the study, 51.3% of children with SCD and 36.5% of adults with SCD who had COVID-19 required exchange transfusion during hospitalization. The treatment provided rapid improvement of tachypnea, dyspnea, and oxygen saturation, improving the clinical course in those who required respiratory support in the ICU. The study also showed that 50% of children and 41.8% of adults with SCD and COVID-19 were on HU therapy. The authors posited several benefits of HU therapy in this patient population, including levels of HbF, hemolysis, platelets, leukocytes, and inflammatory parameters such as interleukin 6. However, they recommended more research to establish the benefits of HU therapy in this patient population.