Prevalence and Monitoring of Diabetes Among Adults with Sickle Cell Disease: A Single Institution Experience

Background: Sickle cell disease (SCD) is the most common hereditary red blood cell disorder in the United States (USA) and primarily affects African-Americans. Of the four most common sickle cell genotypes, SS and Sβ0 are associated with greater severity, including more ischemia due to sickling and more profound microvascular changes from chronic sickling, as compared to those with the Sβ+ and SC genotypes. African-Americans suffer from high rates of Type 2 Diabetes mellitus (T2DM), a disease associated with deleterious microvascular changes when blood glucose is poorly controlled. Recent epidemiologic studies suggest the prevalence of T2DM among African-Americans with and without SCD in the USA are similar around 15-20% and that patients with SCD and T2DM are more likely to be overweight than those without T2DM (Zhou etal., Br J Haematol, 2019). However, the prevalence of diabetes among the different genotypes of SCD remains unknown (Skinner etal., Br J Haematol, 2019). Furthermore, the HbA1C, which is often used to screen, diagnose and monitor long-term control of T2DM in patients is not reliable in patients with SCD and data suggests that fructosamine may be a more reliable marker in this patient population (Smaldone, 2008). If SCD patients with T2DM are undiagnosed or undertreated, they may develop preventable complications related to their vasculopathy. In this study, we assessed both the prevalence of T2DM among adults with various SCD genotypes at our institution and the methods of monitoring long-term control among these patients. Methods: The University of North Carolina (UNC) Sickle Cell Database was used to conduct a single- institution, retrospective cross-sectional study of sickle cell patients and matched controls. A query of electronic medical records identified adult patients > 18 years old with both SCD (SC, Sβ+, SS, or Sβ0) and T2DM seen in the UNC Hospital system in the past 5 years Age, race, gender, BMI, and the frequency of fructosamine and HbA1C values were evaluated. Patients were divided into 2 groups - less severe (SC/Sβ+) vs. more severe (SS/Sβ0). Controls without T2DM were randomly selected from the database and matched 2:1 to cases based on SCD genotype, age, race, and gender for body mass index (BMI) comparisons. Unadjusted statistical tests were used to examine how the group with the more severe SCD genotype (SS/Sβ0) differed from the less severe genotype group (SC/Sβ+) based on T2DM diagnosis and BMI. Results: We identified