Long-term persistency and costs associated with the use of iron chelation therapies in the treatment of Sickle cell disease within Medicaid programs

Objective: This retrospective study evaluated iron chelating therapy (ICT) discontinuation and costs in Sickle cell disease (SCD) Medicaid recipients using healthcare claims from 2006-2010. Methods: Patients with ≥1 SCD diagnosis claim, ≥2 claims for deferoxamine (DFO) or deferosirox (DFX), and continuous enrollment ≥6 months prior to and 18 months following ICT initiation were included. Outcomes included treatment discontinuation, persistence (i.e., refill gaps ≥6 weeks), and total healthcare costs. Results: The average age among 404 SCD patients meeting study inclusion criteria was 18.7 (±11.0) years, with 45.8% being males and 66.7% being Blacks. Switches or combinations from DFO at index occurred in 124 (74.7%) patients compared to 10 (4.2%) with DFX at index. The Cox regression model that assessed long-term medication persistence indicated a 1.30-times higher likelihood of treatment discontinuation with DFO compared to DFX (95% CI: 1.06-1.61). Some 19.7% of patient remained on DFX relative to 4.8% on DFO. Both inpatient and total costs were similar in DFX and DFO treatment groups. Following 1 year of treatment, 37.4% remained on DFX compared to 15.7% on DFO. Meaningful differences in treatment discontinuation between the two treatment groups did not occur until 220+ days during the study period. At 18-months, treatment discontinuation rates were high in both groups; 95% for DFO and 80% for DFX. Conclusion: This study of SCD Medicaid patients found more therapeutic switches from DFO to DFX and a higher medication persistency rate with DFX than DFO. The conclusions are limited by the study's retrospective nature, which depends on multivariate statistics to account for patient heterogeneity and risk factors.