The Conundrum of Hydroxyurea Use and Health Care Utilization in Sickle Cell Disease
Authors: Arjunan Akshaya , Moss Deborah , Burns Sydna B. , De Castro Laura M. 
Published: October 2019

Abstract
Introduction: Sickle cell disease (SCD) is a chronic condition associated with a decreased lifespan. Studies in adult and pediatric SCD populations have shown that hydroxyurea (HU) reduces the frequency and intensity of SCD painful events and decreases morbidity. Follow-up studies of MSH patients also showed cost effectiveness and improved survival for HU user. Adequate dosing and continuous daily adherence to HU use are necessary to achieve these benefits. The NIH Consensus Statement on HU Treatment for SCD had identified non-adherence as a major barrier to the effectiveness of HU therapy.The overarching aim of the study wasto describe the pattern of HCU and health quality indicators (HQI) in a SCD population at different ages of the transition period-data submitted in another abstract-. Here we present data supporting patterns of HU utilization and cost in three different SCD patient age-groups.
Methods: We conducted a retrospective data analysis of health insurance claims from a single health plan for service dates 04/01/2016 through 03/21/2017. Members meeting the claims-based definition of SCD (those with any sickle cell related ICD 9/10 CM diagnosis code on two or more separate encounters on distinct dates during the study period) with 12 months of continuous membership were included in the analysis. Only members ages 11-35 years were selected based on study aims and then stratified into three groups representing pre-transition (Group A: 11-18 yr.), transition (Group B: 19-26 yr.), and adult (Group C: 27-35 yr.). Data obtained include demographics, utilization patterns such as: number and cost of Emergency Room (ED) visits, ED reliance rate and total cost of care. Health quality indicators (HQI) such as: hydroxyurea (HU) use, calculated HU medication possession ratio (MPR), influenza (Flu) vaccination status, and total cost and number of visits for PCP and specialists were also obtained. An ED ratio reliance ratio above 0.33 was considered an indicator of excessive reliance. HU medication possession ratio (MPR) of 1.0 was considered complete adherence
Results: One hundred-fourty-four patients, 88 (61%) female, fit the inclusion criteria. Patient number was similarly distributed in all groups: A: 50, B: 48, and C: 46. Medicaid was the primary insurance for 123 (85%) patients, followed by Commercial 15 (10%), and Medicare 6 (5%). The % of HU prescription filled was less than 4 in all three groups, the younger patients -pre-transition group- had 37 % vs. 33% for each of the two group of older patients. HU medication possession ratio was similar and low for all three groups: A=.27, B=.26 and C=.28; 1.0. Those on HU independently of the age groups had a lower rates of both lower and Higher ED reliance rate than those not on HU. For those on HU, the older patients-group C- was the only one with increase of higher ED reliance with compared with those with lower ED reliance (A: 7 vs. 12; B: 5 vs. 7 and C: 9 vs. 4). The Total Cost of Care of the pre-transition group was similar ~$22,000 between those prescribed HU and those not on HU. The total cost of care was twice as much for those study subjects on HU than for those on group B and C ($44,941 and $42,633). Those not on HU in the groups B and C had the lower total care cost ($25,817 and $17,763).
Conclusion: After 20 years of HU approval by the FDA as a disease modifying therapy for SCD, analysis of insurance data regarding HU use, adherence and cost of care in SCD patients before, during and after transition from Pediatric to adult care, still reveals poor adherence and higher overall total care cost but, and lower ED reliance. This Conundrum supports the needs further emphasis on increasing education towards use and adherence to HU therapy, while continuing to develop new therapeutic interventions towards disease modification and cure.

Disclosures
No relevant conflicts of interest to declare.