Supplementary Material for: Real-World Phosphate Binder Use Among Dialysis-Dependent Patients With CKD

Introduction: For patients with chronic kidney disease (CKD), the need for phosphate binder (PB) treatment peaks at onset of dialysis. This real-world study assessed rates of PB utilization and switching in patients with dialysis-dependent CKD (DD-CKD). Methods: We identified patients with PB utilization among those with prevalent DD-CKD using 2018-2019 Medicare Parts A/B/D data. Patients were assigned to cohorts based on primary (most frequently used) PB among calcium acetate, ferric citrate, lanthanum carbonate, sevelamer (hydrochloride and carbonate), sucroferric oxyhydroxide. We measured proportion of patients who were adherent (proportion of days covered >80%) and persistent (patients whose last 90 days of outpatient dialysis reported PB use). Net switching rates were calculated as the difference between switches to and from the primary agent. Results: We identified 136,912 patients with PB use. Proportion of patients adherent ranged from 63.8% (lanthanum carbonate) to 67.7% (sevelamer) and persistent from 85.1% (calcium acetate) to 89.5% (ferric citrate). Most patients (73%) used the same PB throughout the study. Overall, 20.5% of patients experienced one switch and 2.3% two or more. Positive net switching rates were observed for ferric citrate, sucroferric oxyhydroxide, and lanthanum carbonate (2% to 10%) but negative for sevelamer and calcium acetate (–2% to –7%). Discussion/Conclusion: Adherence and persistence rates were low with slight variation across PBs. Net positive switching occurred for ferric citrate, sucroferric oxyhydroxide, and lanthanum carbonate. Further studies are needed to determine the reasons for these findings and could identify opportunities for better control of phosphate levels among patients with CKD.