Table 1.
—Relationship of Age, Laboratory Data, Allergy Skin Tests, eNO, Baseline Spirometry, and Bronchodilator Responsiveness to the DRS of the PC20 in Children With SCA (n = 99)
| Characteristic | Median of Outcome | Range | r | P Value |
| Age, y (n = 99) | 12.8 | 5.6, 19.9 | −0.512 | < .001 |
| LDH, IU/L (n = 90) | 392.5 | 14, 1221 | 0.260 | .013 |
| Hemoglobin, g/dL (n = 97) | 8.1 | 6.0, 12.0 | −0.137 | .180 |
| IgE, kU/I (n = 95) | 32.0 | 2, 1870 | 0.222 | .031 |
| FEV1, % predicteda (n = 99) | 88.1 | 55.7, 122.6 | −0.085 | .413 |
| Bronchodilator response, % change FEV1 (n = 98) | 5.8 | −4.0, 26.2 | 0.129 | .211 |
| FEV1/FVC, % predicteda (n = 99) | 96.0 | 73.6, 109.8 | −0.045 | .664 |
| eNO, ppb (n = 92) | 9.9 | 3.0, 68.0 | −0.101 | .338 |
| Eosinophil, % (n = 97) | 3.0 | 0, 14 | −0.042 | .683 |
| Number of positive skin tests (n = 96) | 0.0 | 0, 8 | −0.051 | .621 |
| WBC, k/mm3 (n = 98) | 11.3 | 1.9, 70.6 | 0.041 | .690 |
DRS = dose response slope; eNO = exhaled nitric oxide; LDH = lactate dehydrogenase; PC20 = provocative concentration of methacholine producing a 20% decrease in FEV1; ppb = parts per billion; SCA = sickle cell anemia.
a
Reference values for pulmonary function based on equations from Wang et al.19