Supplementary Material for: Five-year Time Profiles of Clearances of Different Uremic Solutes in Incident Peritoneal Dialysis Patients

Introduction: Different uremic solutes have varying degrees of clearances owing to different chemical properties and the pathological and physiological changes in the kidneys and peritoneum. Methods: The 5-year time profiles of renal, peritoneal, and total clearances of creatinine, urea nitrogen (UN), uric acid (UA), trimethylamine N-oxide (TMAO), phosphate, beta-2-microglobulin(β2-MG), interleukin-6 (IL-6), indoxyl sulfate (IS), and p-cresol sulfate (PCS) were investigated in 64 peritoneal dialysis (PD) patients. The patients were divided into an early start and a late start group according to baseline estimated glomerular filtration rate to investigate the effect of dialysis initiation timing on uremic solutes clearances. Patients were also divided into incremental peritoneal dialysis (IPD) and full-dose PD groups to investigate the impact of PD strategy on uremic solutes clearances. Results: Peritoneal clearances of creatinine, UN, UA, and phosphate increased over time, while the peritoneal clearance of IL-6 showed a downward trend. The peritoneal clearances of TMAO, β2-MG, IS, and PCS did not change significantly. Patients in early start group showed a lower level of variation and a higher average of renal clearances. IPD patients had a higher level of total clearances of uremic solutes than full-dose PD patients in the first three years after PD initiation. Conclusion: In a long-term follow-up period, the peritoneal clearance of water-soluble small solutes increased over time, but that of protein-bound toxins and middle molecules did not. Initiating PD when residual kidney function remains at a relatively high level and performing IPD may better improve the efficiency of PD and help preserve the renal clearances of uremic solutes.

引言：不同尿毒症溶质因化学特性各异，且肾脏与腹膜存在病理生理改变，其清除率存在不同程度差异。方法：本研究纳入64例腹膜透析（peritoneal dialysis, PD）患者，对肌酐、尿素氮（urea nitrogen, UN）、尿酸（uric acid, UA）、氧化三甲胺（trimethylamine N-oxide, TMAO）、磷酸盐、β2微球蛋白（beta-2-microglobulin, β2-MG）、白细胞介素6（interleukin-6, IL-6）、硫酸吲哚酚（indoxyl sulfate, IS）及对甲酚硫酸盐（p-cresol sulfate, PCS）的肾脏清除率、腹膜清除率及总清除率的5年时间变化曲线进行了分析。根据基线估算肾小球滤过率，将患者分为早期启动组与晚期启动组，以探讨透析启动时机对尿毒症溶质清除率的影响。同时将患者分为递增式腹膜透析（incremental peritoneal dialysis, IPD）组与全剂量PD组，以探究PD治疗策略对尿毒症溶质清除率的影响。结果：肌酐、UN、UA及磷酸盐的腹膜清除率随时间推移逐渐升高，而IL-6的腹膜清除率则呈下降趋势。TMAO、β2-MG、IS及PCS的腹膜清除率无显著变化。早期启动组患者的肾脏清除率变异程度更低，且平均水平更高。在PD启动后的前3年内，递增式腹膜透析组患者的尿毒症溶质总清除率高于全剂量PD组患者。结论：在长期随访期间，水溶性小分子溶质的腹膜清除率随时间升高，但蛋白结合毒素与中分子物质的腹膜清除率无明显变化。在残余肾功能仍处于较高水平时启动PD，并采用递增式腹膜透析策略，可更好地提升PD治疗效率，同时有助于保留尿毒症溶质的肾脏清除率。