One in every 150 babies born in Jamaica has sickle cell anemia (SCA), and one in 10 carries the trait. Yet doctors in Jamaica seldom use standard-of-care treatments for this life-threatening genetic condition. For example, very few children with SCA take hydroxyurea, an oral drug that prevents sickle-related events and reduces clinical interventions such as transfusions and hospitalizations. And patients in Jamaica with SCA who are at high risk for stroke do not receive chronic blood transfusions, which are known to lower the risk. “Low-resource countries like Jamaica are dealing with everything from poverty and an aging health infrastructure to mosquito-borne diseases like dengue and malaria,” says pediatric hematologist Russell Ware, MD, PhD, director of the Division of Hematology at Cincinnati Children’s. “Everything seems like a priority, and it can be challenging for public health leaders to know where to focus. But SCA is an important healthcare priority for Jamaica since it is common there and leads to serious complications like stroke.”

Ware and others at Cincinnati Children’s partner with clinicians in the Caribbean and Sub-Saharan Africa to document the burden of SCA and expand hydroxyurea use to benefit children on a wide scale. He recently led a study with the University of the West Indies in Kingston, Jamaica, which was published in the British Journal of Haematology (Nov. 2021).

The five-year study documents the feasibility and benefits of hydroxyurea (also called hydroxycarbamide) to reduce stroke risk in children who have SCA and no history of primary stroke in low-resource settings without transfusion management. The study, known as EXTEND (EXpanding Treatment for Existing Neurological Disease), was funded by the National Institutes of Health.

For this study, 43 children with sickle cell anemia living in Jamaica were stratified into three risk categories for stroke. Group One had no history of stroke and some exposure to hydroxyurea; Group Two had no history of stroke and no exposure to hydroxyurea; and Group Three had experienced one or more strokes and had no exposure to hydroxyurea.

Study participants were escalated to the maximum tolerated dose of hydroxyurea. They had transcranial Doppler (TCD) with brain magnetic resonance imaging at baseline and after 18 months of hydroxyurea treatment to assess their stroke risk. Doctors evaluated the children periodically for clinical benefits and potential side effects. Not surprisingly, hydroxyurea was more successful in preventing stroke for the first two groups.

The study demonstrates that it is best to use hydroxyurea early for stroke prevention, but that wasn’t the only benefit. “Part of our mission with studies like this is to build capacity in low-resource countries,” Ware says. “Now, by virtue of this study, many more doctors in Jamaica know how to dose hydroxyurea properly, understand which labs to check, and know when to use screening techniques like transcranial Doppler ultrasound for stroke risk. This will improve the overall quality of care for children with SCA in Jamaica and help them experience much better health outcomes.” Ware has been partnering with researchers in low-resource countries like Jamaica, Tanzania and Uganda for more than 10 years to improve care for SCA. The work benefits children who participate in the study and often has a powerful ripple effect. “We start small and create research trials based on the local hospital’s resources and needs,” Ware explains. “Word gets out, and doctors in other areas of the country adopt new treatment approaches and sometimes even push for changes at the governmental level.” 

That’s exactly what happened in Jamaica, where the country’s Ministry of Health and Wellness is considering a request to cover hydroxyurea therapy through public insurance plans. One of Ware’s co-investigators on the EXTEND study submitted the request, citing the study’s results.

For more information, contact Russell.Ware@cchmc.org.