Clinical and laboratory comparisons
Four from the control group declined a blood draw (or had inadequate
sample for processing) and were presumed to be either carriers or have
HBAA genotype given no stigmata of SCD (Table 2). SCD subjects
demonstrated a significantly lower hemoglobin concentration, higher
white blood cell count and lower daytime oxygen saturation level.
A comparison of pulmonary function data is shown in table 3 .
TLC and FEV1 were significantly higher in the healthy
controls compared to those with SCD. There was no significant difference
in LCI among the comparison groups. In our patient cohort, we saw no
changes in LCI with increasing age (Figure 2 )
Amongst the subjects with SCD, a normal pattern of lung function was
noted in 31 patients (91%), an obstructive pattern in 3 patients (9%),
and a mixed obstructive/restrictive pattern in only 1 patient (3%).
Four (12%) of the SCD participants demonstrated bronchodilator
responsiveness. However, nineteen (56%) had a physician diagnosis of
asthma. There was no statistically significant difference in pulmonary
function indices between patients with SCD (n=18) and healthy controls
(n=17) ages 6-12 years. However, a comparison between participants with
SCD and healthy controls ages 13-18 years revealed that TLC and
FEV1 z-score
values were significantly higher in the healthy control group (0.86
+/-1.25 vs -0.22 +/-1.37; P=0.02) and (0.28 +/-1.11 vs -0.53 +/-1.01;
p=0.03).
SCD subjects of all ages without a history of asthma had significantly
higher TLC z-score values vs those with asthma (0.74 +/-1.21 vs -0.32
+/- 1.11 with asthma; p=0.002) but there were no differences in LCI
(7.31 +/-0.65-without asthma vs 7.44 +/-0.83 with asthma; p= 0.5085).
A history of ACS was associated with a lower TLC z-score (-0.74 +/- 0.96
vs 0.41 +/- 1.30, p=0.015) and FEV1 (-0.76 +/- 0.54,
0.08 +/- 1.25; P=0.013). However, a history of ACS was not associated
with higher LCI ((7.25 (0.48) for history of ACS vs 7.47 (0.78);
p=0.411)). A history of asthma or response to bronchodilator was not
significantly associated with LCI