Randomization is not associated with socio-economic and demographic factors in a multi-center clinical trial of children with sickle cell anemia

BACKGROUND: Few studies have investigated factors influencing participation rates for minority children with a chronic disease in clinical trials. The Silent Cerebral Infarct Multi-Center Clinical (SIT) Trial provides an opportunity to study the impact of demographic and socio-economic factors on randomization in a clinical trial among Black children. Our primary objective was to characterize the factors associated with successful randomization of children with sickle cell disease (SCD) and silent cerebral infarct (SCI) in the SIT Trial after initial consent. PROCEDURE: Differences in socio-economic and demographic variables, family history and disease-related variables were determined between eligible participants who were successfully randomized and those who were not randomized following initial consent. Head of household educational level and family income were examined separately for US versus non-US sites. RESULTS: Of 1,176 children enrolled in the SIT Trial, 1016 (86%) completed screening. Of 208 (20%) children with SCI on screening MRI, 196 (94%) were successfully randomized. There were no differences in socio-economic, demographic or disease-related variables between children who were or were not randomized. Participants from non-US sites were more likely to be randomized (22% vs. 12%, p = 0.011), although randomization by country was associated with neither head of household education nor family income. CONCLUSION: In the SIT Trial, randomization after initial consent does not appear to be associated with socio-economic or demographic factors. Although these factors may represent barriers for some participants, they should not bias investigators caring for children with SCD in their approach to recruitment for clinical trial participation

Children with sickle cell anemia with normal TCD and without silent infarcts have a low incidence of new strokes

In a prospective cohort study, we tested the hypothesis that children with sickle cell anemia (SCA) with normal transcranial Doppler ultrasound (TCD) velocities and without silent cerebral infarcts (SCIs) would have a lower incidence rate of new neurological events (strokes, seizures or transient ischemic attacks) compared to children with normal TCD measurements and SCIs, not receiving regular blood transfusions. Non-randomized participants from the Silent Cerebral Infarct Transfusion (SIT) Trial who had screening magnetic resonance imaging (MRI) of the brain and normal TCD measurements were included. Follow-up ended at the time of first neurological event, start of regular blood transfusion, or loss to follow-up, whichever came first. The primary endpoint was a new neurological event. Of 421 participants included, 68 had suspected SCIs. Mean follow-up was 3.6 years. Incidence rates of new neurological events in non-transfused participants with normal TCD values with SCIs and without SCIs were 1.71 and 0.47 neurological events per 100 patient-years, respectively, p=0.065. The absence of SCI(s) at baseline was associated with a decreased risk of a new neurological event (hazard ratio 0.231, 95% CI 0.062 - 0.858; p=0.029). Local pediatric neurologists examined 67 of 68 participants with suspected SCIs and identified 2 with overt strokes classified as SCIs by local hematologists; subsequently one had a seizure and the other an ischemic stroke. Children with SCA, without SCIs, and normal TCD measurements have a significantly lower rate of new neurological events when compared to those with SCIs and normal TCD measurements. Pediatric neurology assessment may assist risk stratification. This article is protected by copyright. All rights reserved.</p