Table 1.
Participants’ characteristics.
| All (N = 113) | HbSS only (N = 99) | |
|---|---|---|
| Age (years), median (IQR) | 14 (10–20) | 14 (10–28) |
| Age group (years), n (%) | ||
| Children (<12) | 37 (32.7%) | 29 (29.3%) |
| Adolescents (12–17) | 26 (23%) | 26 (26.3%) |
| Young adults (≥18) | 50 (44.3%) | 44 (44.4%) |
| Female, n (%) | 57 (50.4%) | 52 (52.53%) |
| Sickle cell genotype, n (%) | ||
| HbSS | 99 (87.6%) | 99 (100%) |
| HbSC | 9 (8%) | – |
| Othera | 5 (4.4%) | – |
| HU indication, n (%) | ||
| Recurrent pain | 35 (46.1%) | 25 (38.5%) |
| CNS diseaseb | 11 (14.5%) | 11 (16.92%) |
| Recurrent acute chest syndrome | 5 (6.6%) | 13 (20%) |
| ≥1 of above indications | 11 (14.5%) | 11 (16.92%) |
| Othersc | 12 (17.2%) | 13 (20%) |
| HU dose (mg/kg/dose), median (IQR) | 27.5 (23.3–30.8) | 28 (24–32) |
| HU formulation, n (%) | ||
| Liquid | 18 (16.2%) | 17 (17.5%) |
| Tablet | 93 (83.8%) | 80 (82.5%) |
| HU MTD,d n (%) | 13 (11.6%) | 13 (13.4%) |
| HU duration (months), median (IQR) | 47 (20–60) | 47 (20–60) |
| Chronic pain, n (%) | 20 (17.7%) | 17 (17.2%) |
| Cholecystectomy, n (%) | 19 (16.8%) | 17 (17.2%) |
| Splenectomy, n (%) | 11 (9.7%) | 9 (9.1%) |
| Insurance, n (%) | ||
| Private | 64 (56.6%) | 60 (60.6%) |
| Public/Medicaid | 44 (38.9%) | 34 (34.3%) |
| Combinede | 4 (3.5%) | 4 (4%) |
| None | 1 (0.9%) | 1 (1%) |
| Distance to hospital (miles), median (IQR) | 15.2 (9.5–30.9) | 14.3 (9.5–30.6) |
| Laboratory markers (most recent), median (IQR) | ||
| Foetal haemoglobin (%) | 14.5 (8.2–28.1) | 15.3 (9.1–28.8) |
| Mean corpuscular volume (fl) | 99.6 (90.4–112.5) | 102.3 (92.6–112.9) |
| Absolute neutrophil count (103/ml) | 3.8 (2.5–5.9) | 3.8 (2.4–6) |
| SCD emergency room visits on HU (rate/year), median (IQR) | 0.27 (0–2.0) | 0.2 (0–1.6) |
| SCD hospitalizations on HU (rate/year), median (IQR) | 0.33 (0–1.4) | 0.24 (0–1.4) |
| SCD inpatient LOS on HU (days/year), median (IQR) | 1 (0–20.6) | 0.67 (0–5.2) |
HU: hydroxyurea; LOS: length of stay; MTD: maximum tolerated dose; SCD: sickle cell disease.
aOther genotype included HbSβ+ (n = 2), HbSβ0 (n = 2), HbS/Alpha-Thalassemia (n = 1).
bCNS disease defined as stroke or abnormal transcranial Doppler.
cOther hydroxyurea indications included poor growth (n = 5), anaemia (n = 3), transition from chronic transfusion (n = 3), hypoxia (n = 1), and abnormal imaging (n = 1). The remainder were not located in the EMR (n = 37).
dMaximum tolerated dose was 35 mg/kg/d.
eCombined insurance is referring to patients who had both public then private insurance over time, or vice versa.