Stroke in sickle cell children reduced through blood transfusions

Children receiving blood transfusions for sickle cell anemia saw a 56 percent reduction in the risk for stroke in a study published Aug. 21 in the New England Journal of Medicine.

Sickle cell anemia increases risk for stroke with as many as one in three children experiencing silent cerebral infarcts. Risk for damaging, life-limiting stroke in sickle cell patients increases as they enter adulthood.

Michael R. DeBaun, MD, MPH, of the Vanderbilt–Meharry Center of Excellence in Sickle Cell Disease at Vanderbilt University School of Medicine in Nashville, Tenn., and colleagues worked with 196 children divided into randomized groups: those who underwent transfusions and those who were under observation (standard care). These children were between 5 and 15 years of age.

After three years of follow-up, 6 percent of the transfusion group and 14 percent of the observation group experienced either a silent or hemorrhagic stroke. Further analysis put the incidence rate of stroke recurrence at 2 per 100 person-years for transfusion patients and 4.8 per 100 person-years for patients receiving standard care. When transient ischemic attacks were included in the review of risk of cerebral events, while risks remained the same for the transfusion patients, risk increased in the observation group to 5.6 per 100 person-years.

This translated into risk for recurrent stroke having been reduced by 58 percent for children with sickle cell who received transfusions. Factors that appeared to have a relation to increased risk of recurrent stroke were history of recurring headaches (odds ratio, 4.33), younger age (odds ratio, 1.41) and higher steady-state reticulocyte count (odds ratio, 1.41).

Younger children were, apparently, more likely to have a recurrent stroke. While MRI was difficult in patients under 6-years-old without sedation, DeBaun et al suggested that patients with sickle cell anemia should have at minimum one nonsedated MRI as they begin elementary school as a precaution.

Martin H. Steinberg, MD, of Boston University School of Medicine, wrote in an editorial that “the study raises important questions for pediatricians and especially for internists who see these patients after many years of treatment, when untoward consequences of chronic transfusion can be present.” Steinberg continued by questioning if complications of long-term transfusion outweigh the benefits and whether benefits could be sustainable.

Indeed, DeBaun et al noted it would be difficult to recommend this therapy for all sickle cell anemic patients at this time. They noted that with risks and costs inherent in blood transfusions, research was needed to determine which children would be at greatest risk for recurrence in order to accurately and appropriately target therapy.

However, the team remained optimistic about the benefits of transfusion in sickle cell children to prevent recurrent stroke.

Co-author Michael J. Noetzel, MD, of Washington University School of Medicine in St. Louis, stated in a press release, “Now that we have identified a viable treatment option, early detection of silent cerebral strokes should become a major focus for clinicians and families of children with sickle cell disease.” Noetzel also stated that the data point to transfusion as significantly preventative.

Allison King, MD, another co-author also from Washington University School of Medicine, noted that transfusions help by lowering the amount of sickle-shaped cells, and thereby the cerebrovascular damage they cause. “Keeping the sickled cells to less than 30 percent seems to be ideal.”

Steinberg wrote that this research showed the effectiveness of transfusion therapy in the short term on reducing cerebrovascular disease progression in sickle cell patients. Like DeBaun et al, Steinberg noted that additional research was needed to see long-term, clinical benefits for these patients.