African Sickle Beta Zero-Thalassemia Patients Vs Sickle Cell Anemia Patients: Similar Clinical Features but Less Severe Hemolysis - Abstract
Introduction: S-? zero thalassemia (S?0) represents less than 5% of the sickle cell disease (SCD) phenotypes. Although the S?0 phenotype is believed to be as severe as the homozygous (SS) sickle cell anemia, the two phenotypes have rarely been compared.
Objectives: To compare the clinical and biological features of S?0 and SS patients.
Methods: We conducted a nested case-control study within the CADRE cohort, including 3747 SCD patients in five sub-Saharan African countries. The SCD phenotype was established using hemoglobin electrophoresis results (i.e. absence of HbA, HbA2>3.5%) in combination with low mean glomerular volume (<78 fL). We studied the characteristics of 152 S?0 patients and 1353 SS patients matched by age and country and compared the two groups using a multivariate conditional regression analysis.
Results: There was no significant difference between the two groups in terms of clinical complications but S?0 patients displayed less frequent microalbuminuria (24% vs 41%, p=0.02), a lower hemolysis level as assessed by the hemoglobin (8.8 vs 8.2 g/dL, p<0.0001), LDH (551 vs 732 IU/L, p=0.021)
and bilirubin levels (23 vs 33 µmol/L, p=0.0001), and a higher percentage of fetal hemoglobin (14.5 vs 8.8%, p=0.002).
Conclusion: Overall, our study conducted in West Africa confirms the similarity between S?0 and SS phenotypes regarding most clinical features except for the hemolysis level and the glomerular involvement that are less severe in S?0 than in SS phenotype.