Sickle Cell Disease Associated With Severe COVID-19, Mortality

Patients with sickle cell disease (SCD) were more affected by COVID-19, leading to more severe cases and mortality, compared with healthy individuals, according to a meta-analysis published in the Journal of Medical Virology. Timely diagnosis and treatment are necessary to avoiding adverse effects of COVID-19 in this population.

Severe COVID-19 has been previously linked to the presence of common diseases, including cardiovascular disease, cancers, and diabetes. Patients with SCD, an inherited disorder of hemoglobin molecular dysfunction, have immunodeficiency, anemia, organ damage, inflammatory responses, and other comorbidities. Research into how the COVID-19 virus affects those with SCD has not been done. This review aimed to find the relationship between SCD and severe COVID-19.

Young African American man sitting on the couch at home and coughing | Image credit: Tetiana - stock.adobe.com

The authors of this meta-analysis used PubMed, Web of Science, and Embase to systematically collect papers until August 20, 2023. Patients with combined SCD and sickle cell trait (SCT) who had COVID-19 were considered the case group whereas the control group were patients who had COVID-19 but not combined SCD/SCT. Studies that were published in English and reported effect sizes were included in the review. Articles that were not published in English; were meta-analyses, case reports, reviews, news comment, guideline, or expert consensus; were animal-based; were repeated articles; or lacked sufficient information were excluded from the meta-analysis.

A total of 21 studies were included in this meta-analysis: 4 from Europe, 13 from North America, 3 from Asia, and 1 from Africa. There were 14 studies that reported on the relationship between SCD and COVID-19 hospitalization, 7 that reported on SCD and intensive care unit (ICU) admission, 8 articles that reported on SCD and mortality, and 4 that reported on SCD and respiratory failure. All but one study were cross-sectional studies, with the remaining one being a cohort study.

The findings in the studies showed that there was a significant relationship between SCD and an increased risk of mortality (pooled effect size [ES], 1.70; 95% CI, 1.00-2.92), hospitalization (pooled ES, 6.21; 95% CI, 3.60-10.70), and ICU admission (pooled ES, 2.29; 95% CI, 1.61-3.24) compared with those who did not have SCD. There was an increased risk of respiratory failure/mechanical ventilation in patients with SCD but the statistical association was not found.

There was also a statistically significant relationship between SCT and a higher likelihood of mortality (pooled ES, 1.54; 95% CI, 1.28-1.85) and hospitalization (pooled ES, 1.20; 95% CI, 1.07-1.35). There was no association between risk of ICU admission or risk of mechanical ventilation in patients with COVID-19 and SCT.

There were some limitations to this analysis. Only articles published in English were included in this review, which could have led to the exclusion of other suitable studies and overall publication bias. More prospective studies are needed to verify the results, as this analysis mostly consisted of retrospective studies. Some confounding factors that could influence the results were not excluded due to unadjusted crude effect values being included.

The authors concluded that SCD has an effect on the mortality and severity of COVID-19, with patients with SCD being more likely to experience more severe forms of the virus. Further research into the relationship is needed.

Reference

Liang T, Guo K, Ni P, Duan G, Zhang R. The association of sickle cell disorder with adverse outcomes in COVID-19 patients: a meta-analysis. J Med Virol. 2023;95:e29120. doi:10.1002/jmv.29120