To the Editor: In their observational study,
Dr Steinberg and colleagues1 concluded that
hydroxyurea is associated with a lower risk of myelodysplasia and acute leukemia
among patients with sickle cell anemia (SCA) than among those with myeloproliferative
I am concerned, however, that the authors did not follow up the patients
for long enough to detect such adverse effects of hydroxyurea. Although the
mean follow-up was 7.6 years, most of the patients received hydroxyurea for
less than 37 months. Furthermore, only 94 patients received it for 5 or more
years. By contrast, Najean and Rain2 found
that among elderly individuals with polycythemia vera, the risk of acute leukemia
was not significantly increased until after 8 years of continuous use of hydroxyurea.
In the study of Steinberg et al, only 23 patients received hydroxyurea for
at least 8 years.
Spell DW. Long-term Use of Hydroxyurea for Sickle Cell Anemia. JAMA. 2003;290(6):752. doi:10.1001/jama.290.6.752-a
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