Nationwide examination of access to comprehensive care in sickle cell disease

The National Heart, Lung, and Blood Institute awarded the University of North Carolina at Chapel Hill $171,488 on September 30, 2025, under the Cardiovascular Diseases Research program (CFDA 93.837) to conduct a nationwide examination of access to comprehensive care in sickle cell disease.

The research uses national Medicaid insurance claims data to address two analytic aims. The first aim identifies three groups of people with sickle cell disease—those who do not receive care from a hematology provider, those who receive hematology care but not at a comprehensive sickle cell center (CSCC), and those who receive care at a CSCC—and characterizes sociodemographic factors associated with not receiving CSCC care. The second aim applies instrumental variable (IV) analysis, a quasi-experimental econometric approach that accounts for bias in observational data, to estimate the causal effect of CSCC care on mortality and health care utilization, using differential distance to a CSCC as an instrument. The research will provide the first national description of population-level access to comprehensive sickle cell care and robust evidence of the impact of receiving care at a CSCC.

Work is performed in Chapel Hill, North Carolina, with a period of performance through August 31, 2026. The award is a Project Grant, an assistance type under the NHLBI's Cardiovascular Diseases Research program.

Abstract

Sickle cell disease (SCD) is a complex and highly morbid inherited blood disorder that affects at least 100,000 people in the US. IT is associated with a 20-year reduction in life expectancy and substantial economic costs to the health care system. Research and clinical care for SCD has faced challenges from a lack of population- level registry data and a historic paucity of specialist care relative to comparator inherited diseases like hemophilia or cystic fibrosis. Recent years have seen an increased focus on the development of comprehensive sickle cell centers (csccs); however, we do not know how many people with SCD have access to csccs at a population level, nor do we know the impact of receiving care at these centers on health-related outcomes. To address these gaps in knowledge, we propose two analytic aims using national insurance claims data from medicaid, which insures the majority of people with SCD in the US. In the first aim, we will identify three groups of people with SCD: those who a) do not receive care from a hematology provider, b) receive care from a hematology provider but not at a cscc, and c) receive health care at a cscc, and we will identify sociodemographic characteristics associated with not receiving care at a cscc. The second aim will use an econometric approach called instrumental variable (IV) analysis, which is a quasi-experimental design that accounts for bias in observational data to produce estimates of causal effect. We will use IV analysis to estimate the causal effect of receiving care at a cscc on mortality and health care utilization, using differential distance to a cscc as an instrument. The proposed research will provide the first national description of access to comprehensive care for people with SCD and the most robust estimate of the impact of receiving comprehensive care to date. These results will help health care providers consider the role of csccs for people with SCD, and they will inform policymakers' discussions about allocation of resources toward comprehensive care in SCD. This work will also provide critical training to the applicant in the form of mentorship in SCD and advanced research methodology as he pursues his goal of becoming an independent health services researcher in SCD.