In a new study, researchers found that patients with sickle cell disease (SCD) who have a history of pain, in addition to other factors, appear to be at increased risk of serious COVID-19 illness. The results of this study were published in the journal Blood Advances.

This study included pediatric and adult patients with SCD who were included in the Surveillance Epidemiology of Coronavirus Under Research Exclusion for Sickle Cell Disease (SECURE-SCD) Registry. Patients were included from multiple countries. Hospitalization and serious COVID-19 illness were the primary study outcomes. Seriousness of COVID-19 illness was determined based on clinical criteria for categories ranging from asymptomatic to critical illness. “Serious” illness included moderate, severe, and critical categories, and it excluded asymptomatic or mild cases. Outcomes were analyzed with respect to numerous patient and clinical characteristics using multivariable logistic models.

A total of 750 patients with SCD and COVID-19 illness were identified in the registry by March 23, 2021. Of these, 386 were adult patients, and 364 were children, defined as below 18 years of age. Adult patients had a median age of 31 years (interquartile range [IQR], 24-40), and pediatric patients had a median age of 11 years (IQR, 6-15). COVID-19 severity was moderate in 9.3% of children and 17.4% of adults. It was severe in 7.1% of children and 14.2% of adults, and it was critical in 1.1% of children and 2.8% of adults. Death was reported in 1 pediatric patient (0.3% of children) and in 18 adults (4.7% of adults).

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In children, risk factors found to be associated with hospitalization included history of pain (relative risk [RR], 2.15; P <.0001) and SCD-related heart/lung comorbidities (RR, 1.61; P =.0001). Serious COVID-19 illness in children was associated with SCD-related renal comorbidities (RR, 3.67; P <.0001), history of pain (RR, 3.09; P =.0009), and SCD-related heart/lung comorbidities (RR, 1.76; P =.03). Risk of pain as a presenting symptom in pediatric patients with COVID-19 was also higher with a pain history or SCD-related renal comorbidities.

Hospitalization in adults was linked to history of pain (RR, 1.78; P =.002). For adults, serious COVID-19 illness was also associated with a history of pain (RR, 1.94; P =.02), in addition to age (RR, 1.04; P =.002). Pain risk was higher in adult patients with COVID-19 in the presence of pain history, female sex, and SCD-related heart/lung comorbidities. Although it did not affect COVID-19-specific outcomes for adults or children, hydroxyurea was associated with a decreased risk of pain as a presenting symptom in adults with COVID-19 (P =.02).

“In conclusion, our findings show that history of pain, SCD-related heart and lung comorbidities, and SCD-related renal comorbidities are risk factors for worse outcomes of COVID-19 illness in children; history of pain is a risk factor in adults,” the researchers wrote in their report.


Mucalo L, Brandow AM, Dasgupta M, et al. Comorbidities are risk factors for hospitalization and serious COVID-19 illness in children and adults with sickle cell disease. Blood Adv. 2021;5(13):2717-2724. doi:10.1182/bloodadvances.2021004288