Details
Hydroxyurea, an antineoplastic agent, was approved in 1998 to reduce the frequency of sickle cell crises in adult patients with sickle cell disease (SCD). More recently in 2017, hydroxyurea was also approved for pediatric patients, 2 years of age and older with sickle cell anemia and recurrent moderate to severe painful crises. Prior to this, hydroxyurea had been used in the United States (US) in pediatric patients with SCD without a labeled indication. This study investigated hydroxyurea utilization patterns among pediatric and adult patients with SCD in the US prior to the pediatric approval using administrative claims data in the Sentinel database sponsored by the US Food and Drug Administration.
Data from 17 health plans contributing to the Sentinel Distributed Database were queried from January 1, 2000 through September 30, 2015. Eligible patients had a claim with a diagnosis of SCD in any care setting at any time during the query period. SCD was identified using International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) diagnosis codes. Patients were required to be enrolled in plans with both medical and drug coverage on the date of their SCD diagnosis. Patients who were dispensed hydroxyurea after diagnosis of SCD were identified as hydroxyurea users. Patients included in the sub-analysis evaluating hydroxyurea cumulative duration of therapy were required to be continuously enrolled with medical and drug coverage for at least 90 days prior to the initial hydroxyurea dispensing date, during which, gaps in coverage of up to 45 days were allowed. For this sub-analysis, follow-up began on the day of the first valid hydroxyurea dispensing and continued until the first occurrence of any of the following: 1) disenrollment; 2) death; 3) the end date of the data provided by each Data Partner; 4) the end of the last hydroxyurea exposure episode; or 5) the end of the query period. Cumulative duration of hydroxyurea therapy was calculated by summing days' supplies from outpatient pharmacy hydroxyurea dispensings for each patient. Results were stratified by age group (≤1, 2-5, 6-11, 12-17, 18-49, and 50+ years) and race.