The Role of Hemoglobin F in Sickle Cell Disease Complications: A Descriptive Secondary Analysis Open Access

• There was no effect of age, hemoglobin F, or sex on thrombotic events using a logs-odds scale (p=0.35, p=0.13, and p=0.39 respectively)

• Pulmonary hypertension is associated (p = 0.022) with a lower median HbF level

Individuals with sickle cell disease, a prevalent inherited blood disorder, are at increased risk for tissue ischemia and thrombosis secondary to sickle hemoglobin polymerization. Fetal hemoglobin protects against the vaso-occlusive nature of sickled erythrocytes. Our study aims to investigate the association between fetal hemoglobin level and various SCD complications. It uses a descriptive and cross-sectional design to analyze existing, secondary medical record data of 496 SCD patients that received care from the Center for Blood Disorders in Augusta, Georgia. Of these, only patients with HbSS and HbSβ0 thalassemia (n=273) were used for analysis. Data abstraction included history of thrombotic event (TE) and HbF values closest to the TE, along with, presence of SCD clinical complications, use of anticoagulation medications, specific lab values, and hemoglobin electrophoresis. These patients were reflective of the greater population of sickle cell patients in that they had similar rates of complications like avascular necrosis and sickle cell retinopathy compared to nationally reported data. We found a significant association between incidence of thrombosis and higher hemoglobin F (HbF) levels (p=0.034). The presence of HbF was also found to influence the incidence of complications, including avascular necrosis and pulmonary hypertension. When stratified into quantiles, there was a relationship between HbF and incidence of AVN in male patients (p=0.038). Further research is warranted to investigate if other treatments for SCD produce similar results and if this effect is representative of other large patient populations with SCD.