Stroke and Neurodevelopmental Delays in Sickle Cell Disease

Abstract

In the United States of America, Sickle Cell Disease (SCD) affects 100,000 Americans, predominantly African Americans. In North Carolina (NC), there are approximately 5,578 people living with SCD, which includes both children and adults. Of those affected, 39% are 18 years of age or younger. Strokes are a major disease-related complication that children with SCD too often experience. Some complications include motor and cognitive delays, neurodevelopmental delays (NDD), decline in academic learning and attainment, poor test scores, high school dropout and/or unemployment (later in life). The purpose of this dissertation was to address the problems of stroke prevention and NDD in children with SCD. Therefore, we analyzed hydroxyurea (HU) adherence as well as transcranial Doppler (TCD) screening prevalence and proportion in a statewide Medicaid sample in an attempt to evaluate primary stroke prevention in children ages 2 to 16 years old with SCD. The purpose of this dissertation was achieved through a systematic literature review that explored the prevalence, severity, and associated risk factors for NDD in children with SCD less than or equal to 5 years. Secondary data analyses of the NC Medicaid database was used to examine the following: 1) HU adherence rates for 12- and 24-month cohorts; 2) associations of individual related sociodemographic characteristics with HU adherence; 3) the prevalence rate of children with annual TCD screenings; 4) the proportion of children with zero, 1, 2, 3 or more TCD screening claims; and 5) the prevalence rate of TCD screening claims for age, sex, residential location, and HU adherence. The methods used in the data chapters were descriptive statistics, frequencies, percentages, and chi-square was used to determine differences in HU adherence for both the 12 and 24-month cohorts (Chapter 3), Cochran-Armitage Trend Test and the Cochran-Mantel-Haenszel Test were used to evaluate the proportion of TCD claims with 2, 3, and more levels (Chapter 4), and a Poisson Regression was used to fit the effect of TCD screening claims on sociodemographic characteristics, HU adherence, and to determine the rate of TCD screenings for each of the individual predictor variables (Chapter 4). The findings from this dissertation highlighted a wide range of motor and language deficits among children ages 0 to 5 years old with SCD (Chapter 2). Other major findings included low HU utilization (Chapter 3) and low TCD screening prevalence (Chapter 4) among children ages 2 to 16 years old with SCD on NC Medicaid. Additionally, children with poor HU adherence were less likely to have TCD screening claims (Chapter 4). Therefore, tailored interventions are needed to help mitigate the problems of poor HU utilization as well as TCD screening rates among children with SCD.