| dc.description |
Fetal hemoglobin (HbF) and peripheral hemoglobin oxygen saturation (SpO2) both predict clinical severity in
sickle cell disease (SCD), while reticulocytosis is associated with vasculopathy, but there are few data on mechanisms.
HbF, SpO2 and routine clinical and laboratorymeasureswere available in a Tanzanian cohort of 1175 SCD
individuals aged ≥ 5 years and the associationwith SpO2 (as response variable transformed to a Poisson distribution)
was assessed by negative binomial model with age and sex as covariates. Increase in HbF was associated
with increased SpO2 (rate ratio, RR = 1.19; 95% confidence intervals [CI] 1.04, 1.37 per natural log unit of HbF;
p = 0.0004). In univariable analysis, SpO2 was inversely associated with age, reticulocyte count, and log (total
bilirubin) and directly with pulse, SBP, hemoglobin, and log(HbF). In multivariable regression log(HbF) (RR
1.191; 95%CI 1.04, 1.37; p = 0.013), pulse (RR 1.01; 95%CI 1.00, 1.01; p = 0.026), SBP (RR 1.008; 95%CI 1.00,
1.02; p=0.014), and hemoglobin (1.120; 95%CI 1.05, 1.19; p=0.001) were positively and independently associated
with SpO2 while reticulocyte count (RR 0.985; 95%CI 0.97, 0.99; p =0.019) was independently inversely
associated with SpO2. In SCD, improving SpO2, in part through cardiovascular compensation and associated with
reduced reticulocytosis, may be a mechanism by which HbF reduces disease severity. |
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