Data Sheet 1_Complications and treatment patterns in patients with non-transfusion-dependent α- and β-thalassemia compared with matched controls: a retrospective observational study using administrative claims data in the United States.docx

BackgroundNon-transfusion-dependent thalassemia (NTDT) can result in a range of clinical complications that can substantially reduce patient quality of life. To date, real-world studies on the clinical burden of the disease have focused on Europe and Asia and have been limited to β-NTDT.
AimTo assess the complications and treatment patterns in patients with α- or β-NTDT vs. matched controls in the United States (US).
MethodsThis retrospective observational study used data from US claims databases (January 1, 2013–June 30, 2021). Adult patients (≥18 years) with ≥1 inpatient or ≥2 outpatient claims for α- or β-thalassemia were included from Merative™ MarketScan® Commercial/Medicare and Multi-State Medicaid databases. Patients were classified as NTDT if they had <8 blood transfusions or ≥6 weeks between any two adjacent transfusions during the 12 months post-index date (date of first observed α- or β-thalassemia diagnosis code). Patients were matched with controls (1:5 ratio). Primary analysis focused on patients from the Commercial/Medicare database with mean hemoglobin <10 g/dL during follow-up, to minimize inclusion of patients with thalassemia trait. Complications and treatment patterns were assessed during ≥12 months post-index. Comparisons between patients with NTDT vs. controls were performed using Chi-square tests (categorical variables) and t-tests (continuous variables) (two-sided significance level of 0.05). Analyses for the α- and β-NTDT subgroups were also performed.
ResultsIn the Commercial/Medicare database, 149 patients with NTDT and hemoglobin <10 g/dL were matched with 745 controls (mean follow-up approximately 3 years). A significantly higher percentage of patients with NTDT had complications vs. controls, including malignancy (17.4% vs. 7.1%; p < 0.001), cardiovascular disease (15.4% vs. 7.8%; p = 0.003), liver disease (6.7% vs. 0.5%; p < 0.001), and gallstones (6.7% vs. 2.1%; p = 0.002). Overall, 18.8% of patients with NTDT had ≥1 transfusion; 4.0% received oral chelators. Similar trends across outcomes were observed for NTD α- and β-thalassemia subgroups vs. controls.
ConclusionsPatients with NTDT had a high disease burden and experienced a range of serious complications, with significantly higher rates compared with controls. Additional effective and well-tolerated treatments are needed to address the underlying causes of NTDT and prevent complications.