Hydroxyurea is safe, effective, and affordable for patients with sickle cell disease (SCD), yet it is an underutilized treatment option, according the American Journal of Hematology.

Researchers sought to update the evidence on hydroxyurea adherence, in addition to its association with clinical and economic outcomes, in those with SCD. The current analysis used Texas Medicaid claims data between September 2011 and August 2016.

Participants were included who had 1 or more inpatient or 2 or more outpatient SCD diagnoses, had 1 or more hydroxyurea prescription, were continuously enrolled in Texas Medicaid from 6 months before to 1 year after their first hydroxyurea prescription fill date (ie, the index date), and were between 2 and 63 years of age.

The study evaluated hydroxyurea adherence (medication possession ratio), vaso-occlusive crisis (VOC)-related outcomes, health care utilization, and expenditures (SCD-linked and all-cause) following the index date.

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VOC, which is characterized by a recurrent, unpredictable attack of acute pain, is a key contributor to the disease burden and costs associated with SCD. It is well known that until 2017, hydroxyurea (hydroxycarbamide) was the only US Food and Drug Administration-approved disease-modifying pharmacologic therapy to demonstrate beneficial effects in reducing the number of VOC events, along with hospitalizations and transfusions, in patients with SCD.

The current study enrolled 1035 patients with SCD. The mean participant age was 18.8±12.5 years. Nearly 40% of the study population comprised individuals less than 13 years of age. Overall, 52.1% of the patients were female. In all, 20.9% of the participants were adherent to hydroxyurea (which was defined as an medication possession ratio of 0.8 or more).

Following adjustments for demographic and clinical characteristics, compared with nonadherence, adherence to hydroxyurea was significantly associated with a lower risk for a VOC event (odds ratio=0.480, P =.0007, and hazard ratio=0.748, P =.0005); fewer VOC events (incidence rate ratio [IRR]=0.767, P =.0009); fewer VOC-related hospital days (IRR=0.593, P =.0003); fewer all-cause and SCD-related hospitalizations (IRR=0.712, P =.0008 and IRR=0.707, P =.0008, respectively); fewer all-cause and SCD-related emergency department visits (IRR=0.768, P =.0037 and IRR=0.746, P =.0041, respectively); and lower SCD-related total health care expenditures (IRR=0.796; P =.0266).

The authors concluded that, “…to ensure better clinical and economic outcomes among the patients with SCD, multistakeholder efforts to improve adherence to hydroxyurea are warranted.”


Kang HA, Barner JC, Lawson KA, Rascati K, Mignacca RC. Impact of adherence to hydroxyurea on health outcomes among patients with sickle cell disease. Am J Hematol. Published online October 17, 2022. doi:10.1002/ajh.26765