The short-term beneficial effect of hydroxyurea (HU) in sickle cell disease
(SCD) has been proven by randomized studies in children and adults. The Be
lgian registry of HU-treated SCD patients was created to evaluate its long-
term efficacy and toxicity. The median follow-up of the 93 patients registe
red is 3.5 years; clinical and laboratory data have been obtained for 82 pa
tients at 1 year, 61 at 2 years, 44 at 3 years, 33 at 4 years, and 22 after
5 years. On HU, the number of hospitalizations and days hospitalized dropp
ed significantly. Analysis of the 22 patients with a minimum of 5 years of
follow-up confirm a significant difference in the number of hospitalization
s (P = .0002) and days in the hospital (P < .01), throughout the treatment
when compared to prior to HU therapy The probabilities of not experiencing
any event or any vaso-occlusive crisis requiring hospitalization during the
5 years of treatment were, respectively, 47% and 55%. On HU, the rate per
100 patient-years of severe events was estimated to be 3.5% for acute chest
syndrome, 1.2% for aplastic crisis, 0.4% for splenic sequestration; it was
0% for the 9 patients with a history of stroke or transient ischemic attac
k followed for an average of 4 years. No important adverse effect occurred.
Long-term chronic treatment with HU for patients with SCD appears feasible
, effective, and devoid of any major toxicity; in patients with a history o
f stroke, HU may be a valid alternative to chronic transfusion support.