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.

引言：对于慢性肾脏病（Chronic Kidney Disease, CKD）患者而言，磷酸盐结合剂（phosphate binder, PB）的治疗需求在透析启动阶段达到峰值。本项真实世界研究针对透析依赖性慢性肾脏病（Dialysis-Dependent CKD, DD-CKD）患者的磷酸盐结合剂使用比例及换药情况展开评估。
研究方法：本研究依托2018-2019年美国医疗保险A/B/D计划（Medicare Parts A/B/D）数据，筛选出现患透析依赖性慢性肾脏病且使用磷酸盐结合剂的患者。根据患者主要使用（即频次最高）的磷酸盐结合剂类型进行队列分组，涉及药物包括醋酸钙（calcium acetate）、柠檬酸铁（ferric citrate）、碳酸镧（lanthanum carbonate）、司维拉姆（sevelamer，含盐酸盐与碳酸盐两种剂型）以及蔗糖铁氧氢化物（sucroferric oxyhydroxide）。本研究统计了两类患者比例：一是用药依从性达标者（药物覆盖天数占比＞80%），二是用药持续性达标者（近90天门诊透析期间均使用磷酸盐结合剂的患者）。净换药率的计算方式为转入该主要用药的比例与转出比例的差值。
研究结果：本研究共纳入136912名使用磷酸盐结合剂的患者。患者的用药依从率区间为63.8%（碳酸镧组）至67.7%（司维拉姆组），用药持续率区间为85.1%（醋酸钙组）至89.5%（柠檬酸铁组）。多数患者（73%）在整个研究周期内未更换磷酸盐结合剂。整体而言，20.5%的患者仅更换过1次用药，2.3%的患者更换次数达2次及以上。其中，柠檬酸铁、蔗糖铁氧氢化物与碳酸镧组呈现正向净转换率（2%~10%），而司维拉姆与醋酸钙组则为负向净转换率（-2%~-7%）。
讨论与结论：各类磷酸盐结合剂的用药依从率与持续率均处于较低水平，组间仅存在小幅差异。柠檬酸铁、蔗糖铁氧氢化物与碳酸镧组存在正向净用药转换。未来仍需开展进一步研究以阐明本研究结果的潜在机制，并探索改善慢性肾脏病患者血磷水平管控的优化方案。