The role of hemoglobin F in sickle cell disease complications: a descriptive secondary analysis

Individuals with sickle cell disease (SCD), a prevalent inherited blood disorder, are at increased risk for tissue ischemia and thrombosis secondary to sickle hemoglobin polymerization. Fetal hemoglobin (HbF) protects against the vaso-occlusive nature of sickled erythrocytes. Our study aims to investigate the association between HbF level and various SCD complications. The study used a descriptive and cross-sectional design to analyze existing, secondary medical record data of 496 patients with SCD who received care from the Center for Blood Disorders in Augusta, Georgia. Of these, only patients with HbSS and an HbSβ0 thalassemia (n = 273) were included in the 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 laboratory values, and Hb electrophoresis. These patients were reflective of the greater population of patients with SCD in that they had similar rates of complications such as avascular necrosis and sickle cell retinopathy compared with nationally reported data. We found a significant association between incidence of thrombosis and higher HbF levels (P = .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 = .038). Further research is warranted to investigate whether other treatments for SCD produce similar results and whether this effect is representative of other large patient populations with SCD.