Table 1.
Description of the study population
| No disease-modifying therapy (N = 23) | Hydroxyurea therapy (N = 38) | Chronic transfusion therapy (N = 23) | P | |
|---|---|---|---|---|
| Age, median (IQR), y | 11.0 (8.0-21.0) | 11.5 (9.0-23.0) | 15.0 (10.0-20.0) | .940 |
| Sex, female (%) | 11 (47.8) | 17 (44.7) | 14 (60.9) | .460 |
| Genotype | .661 | |||
| Hb SS, n (%) | 20 (87.0) | 33 (86.8) | 22 (95.7) | |
| HbSβ0, n (%) | 3 (13.0) | 5 (13.2) | 1 (4.3) | |
| SpO2, median (IQR), % | 96.0 (94.0-99.0) | 99.0 (97.0-100.0) | 97.0 (96.0-98.0) | .035 |
| Hematologic parameters | ||||
| Hb, median (IQR), g/dL | 7.8 (7.1-8.1)*,† | 8.7 (7.8-9.9)* | 9.1 (8.5-9.8)† | .001‡ |
| Hb A, median (IQR), % | 0.0 (0.0-0.0)† | 0.0 (0.0-0.0)¶ | 52.2 (43.0-63.1)†,¶ | <.001‡ |
| Hb F, median (IQR), % | 7.9 (3.4-14.4)*,† | 17.7 (12.2-25.5)*,¶ | 2.2 (0.0-4.5)†,¶ | <.001‡ |
| Hb S, median (IQR), % | 82.4 (75.1-89.9)† | 78.4 (70.2-83.4)¶ | 41.8 (31.7-49.4)†,¶ | <.001‡ |
| Carboxyhemoglobin, median (IQR), % | 2.7 (2.3-3.7)† | 2.4 (1.8-3.1) | 2.0 (1.9-2.6)† | .023‡ |
| Methemoglobin, median (IQR), % | 2.2 (1.9-2.5) | 2.3 (1.9-2.6) | 1.8 (1.6-2.4) | .206 |
| Neurologic disease | ||||
| Silent infarct, n (%) | 10 (43.5)† | 15 (39.5)¶ | 19 (82.6)†,¶ | .003‡ |
| Overt stroke, n (%) | 0 (0)† | 2 (5.3)¶ | 11 (47.8)†,¶ | <.001‡ |
| Vasculopathy, n (%) | 1 (4.4)† | 2 (5.3)¶ | 10 (43.5)†,¶ | <.001‡ |
HbSβ0, Hb S β thalassemia null disease.
*
Significant difference between cohort not receiving disease-modifying therapy vs cohort receiving HU.
†
Significant difference between cohort not receiving disease-modifying therapy vs cohort receiving CTT.
‡
Statistically significant.
¶
Significant difference between cohort receiving HU vs cohort receiving CTT.