Researchers at UT Southwestern Medical Center have determined that the level, or saturation, of oxygen in blood could be used to identify children with sickle cell anemia who are at an increased risk of stroke.
In a related study, they have also found that a published method used to predict severe complications of the disease may not be adequate.
“Stroke is a serious but increasingly preventable complication of sickle cell disease,” said Dr. Charles Quinn, assistant professor of pediatrics at UT Southwestern and lead author of a study appearing in February's British Journal of Haematology . “Several factors have been identified that increase risk for stroke, but better screening tools are still needed.”
Hemoglobin is an oxygen-transport protein in red blood cells. People with sickle cell disease, including an estimated 100,000 Americans, have a genetic error affecting their hemoglobin. The defect turns normally soft, round blood cells into inflexible, sickle-shaped cells. The altered shape causes blockages in blood vessels and prevents body tissues from receiving oxygen.
The researchers reviewed the cases of 412 children who are part of the Dallas Newborn Cohort, the world's largest group of patients with sickle cell disease who were initially diagnosed by newborn screening. All patients reviewed were born after Jan. 1, 1990, a date chosen because patient data was available electronically.
Oxygen saturation in the children's blood was tracked over time, and the records of those who suffered a stroke were compared to those who did not. The children who had lower levels of oxygen in their blood were more likely to develop stroke, the researchers found.
“A decline in oxygen saturation over time seems to further increase the risk of stroke,” said Dr. Quinn. “Oxygen saturation is easily measured, potentially modifiable and might be used to identify children with sickle cell disease who are at greater risk of having a stroke.”
Another study by Dr. Quinn and his colleagues appeared in the January issue of the journal Blood. That study examined how effectively a model developed by the Cooperative Study of Sickle Cell Disease (CSSCD) predicted severe disease in the newborn cohort.