Toxicity, Dose of HU, Adherence and Two-Year Crisis Rate by HbF Quartile After Two Years of Treatment
| Variable . | Quartile 1 (n = 34) . | Quartile 2 (n = 38) . | Quartile 3 (n = 36) . | Quartile 4 (n = 35) . |
|---|---|---|---|---|
| Toxic > 2 | 47 | 58 | 86 | 94 |
| HU dose (mg/kg)5-150 | % | |||
| <15 | 50 | 34 | 50 | 12 |
| 15-22.5 | 6 | 13 | 22 | 66 |
| 25-32.5 | 9 | 16 | 20 | 20 |
| 35 | 35 | 37 | 8 | 3 |
| ≥80% Visits5-151 | 85 | 90 | 97 | 94 |
| ≥80% Caps5-152 | 56 | 71 | 81 | 83 |
| ≥50% HUρ | 14 | 24 | 28 | 46 |
| Crises/yr5-154 | 6.5 ± 5.9 | 7.2 ± 10.1 | 3.1 ± 5.2 | 2.3 ± 4.5 |
| Variable . | Quartile 1 (n = 34) . | Quartile 2 (n = 38) . | Quartile 3 (n = 36) . | Quartile 4 (n = 35) . |
|---|---|---|---|---|
| Toxic > 2 | 47 | 58 | 86 | 94 |
| HU dose (mg/kg)5-150 | % | |||
| <15 | 50 | 34 | 50 | 12 |
| 15-22.5 | 6 | 13 | 22 | 66 |
| 25-32.5 | 9 | 16 | 20 | 20 |
| 35 | 35 | 37 | 8 | 3 |
| ≥80% Visits5-151 | 85 | 90 | 97 | 94 |
| ≥80% Caps5-152 | 56 | 71 | 81 | 83 |
| ≥50% HUρ | 14 | 24 | 28 | 46 |
| Crises/yr5-154 | 6.5 ± 5.9 | 7.2 ± 10.1 | 3.1 ± 5.2 | 2.3 ± 4.5 |
Toxicity was defined as a neutrophil count < 2,000/μL, reticulocyte count < 80,000/μL, platelet count < 80,000/μL, or hemoglobin concentration < 4.5 g/dL.
Percent of patients on a given dose of HU.
≥80% Visits indicates that ≥80% of scheduled clinic visits were kept.
≥80% Caps indicates that ≥80% of the prescribed HU capsules were taken.
ρ Indicates that HU was present in the serum on ≥50% of HU serum assays.
Crises per year expressed as the 2-year crisis rate ±1 SD.