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Updated: Jun 27, 2025
A Precision Medicine Tool for Measurement and Monitoring of Hemoglobin S in Sickle Cell Disease Patients Receiving Transfusion Therapy
Association of hydroxyurea adherence with transcranial Doppler screenings in children with sickle cell disease
La'Kita M J Knight1, Paula Tanabe2, Audrey L Blewer1,3
1Duke University School of Nursing, Durham, North Carolina, USA.
Insights
Children with sickle cell disease (SCD) need regular transcranial Doppler (TCD) screenings for stroke risk. Better hydroxyurea (HU) adherence and longer enrollment in Medicaid were linked to more TCD screenings in a North Carolina study.
Area of Science:
- Pediatric Hematology
- Neurology
- Public Health
Background:
- National guidelines recommend annual transcranial Doppler (TCD) screenings for children aged 2-16 years with sickle cell disease (SCD) to detect stroke risk.
- Oral hydroxyurea (HU) is recommended starting at 9 months of age for SCD management.
- This study examines TCD screening prevalence and adherence to HU in North Carolina Medicaid enrollees.
Purpose of the Study:
- To determine the prevalence and proportion of annual TCD screenings in children with SCD enrolled in North Carolina Medicaid.
- To investigate associations between TCD screening rates, hydroxyurea (HU) adherence, and sociodemographic factors.
- To evaluate the impact of Medicaid enrollment duration on TCD screening frequency.
Main Methods:
- A longitudinal study analyzed data from North Carolina Medicaid enrollees aged 2-16 years with SCD from 2016-2019.
- Prevalence and proportion of TCD screening claims were calculated over 3 years of enrollment.
- Hydroxyurea (HU) adherence was assessed using the proportion of days covered, and multivariable Poisson regression analyzed TCD screening rates by HU adherence, controlling for age, sex, and rurality.
Main Results:
- The prevalence of annual TCD screening ranged from 39.5% to 40.1%.
- Children with longer Medicaid enrollment showed increased TCD screening rates: 63.3% had one or more claims at 36 months compared to 22.2% at 12 months.
- Children with good HU adherence were 2.48 times more likely to have TCD claims than those with poor adherence (p < .0001).
Conclusions:
- Overall TCD screening prevalence was low, indicating a gap in adherence to national guidelines.
- Improved hydroxyurea (HU) adherence and longer duration of Medicaid enrollment are associated with higher rates of TCD screenings.
- Multilevel interventions targeting healthcare providers and families are necessary to enhance evidence-based care and annual TCD screenings for children with SCD.
Background:
National sickle cell disease (SCD) guidelines recommend oral hydroxyurea (HU) starting at 9 months of age, and annual transcranial Doppler (TCD) screenings to identify stroke risk in children aged 2-16 years. We examined prevalence and proportion of TCD screenings in North Carolina Medicaid enrollees to identify associations with sociodemographic factors and HU adherence over 3 years.
Study Design:
We conducted a longitudinal study with children ages 2-16 years with SCD enrolled in NC Medicaid from years 2016-2019. Prevalence of TCD screening claims was calculated for 3 years, and proportion was calculated for 12, 24, and 36 months of Medicaid enrollment. Enrollee HU adherence was categorized using HU proportion of days covered. Multivariable Poisson regression assessed for TCD screening rates by HU adherence, controlling for age, sex, and rurality.
Results:
The prevalence of annual TCD screening was between 39.5% and 40.1%. Of those with 12-month enrollment, 77.8% had no TCD claims, compared to 22.2% who had one or higher TCD claims. Inversely, in children with 36 months of enrollment, 36.7% had no TCD claims compared to 63.3% who had one or higher TCD claims. The proportion of children with two or higher TCD claims increased with longer enrollment (10.5% at 12 months, 33.7% at 24 months, and 52.6% at 36 months). Children with good HU adherence were 2.48 (p < .0001) times more likely to have TCD claims than children with poor HU adherence.
Conclusion:
While overall TCD screening prevalence was low, children with better HU adherence and longer Medicaid enrollment had more TCD screenings. Multilevel interventions are needed to engage healthcare providers and families to improve both evidence-based care and annual TCD screenings in children with SCD.
