Hemoglobinopathies involved:
(1) sickle cell anemia (hemoglobin SS): mean age of death 42 years for males and 48 years for females
(2) sickle cell hemoglobin C (hemoglobin SC): mean age of death 60 years for males and 68 years for females
(3) sickle cell beta thalassemia (hemoglobin S-beta thal)
Causes of death consequent to sickle cell disease:
(1) associated with overt organ failure
(2) during an acute sickle crisis
Risk factors for early death from multiple regression analysis when the person was 20 years of age or older:
(1) low fetal hemoglobin level (below the 10th percentile) , while a high fetal hemoglobin level (above the 75th percentile, or > 8.6%) was protective
(2) acute chest syndrome
(3) renal failure
(4) seizures
(5) white blood cell count > 15,000 per µL
where:
• The 10th percentile of fetal hemoglobin for the population was not stated. I am using < 3% in the spreadsheet but this is only a guess.
• Patients with hemoglobin SC have a lower level of hemoglobin F than patients with SS.
• If the distribution was Gaussian and the mean fetal hemoglobin and standard deviation are known for the population of patients with sickle cell disease, then the 10th percentile is 1.3 SD below the mean, while 75th percentile is 0.67 SD above the mean. However, the distribution of fetal hemoglobin is probably skewed since the quoted range is 2-20%.
