Ng Jack Kit-Chung, Fung Winston Wing-Shing, Chan Gordon Chun-Kau, Cheng Phyllis Mei-Shan, Pang Wing-Fai, Chow Kai-Ming, Szeto Cheuk-Chun
Carol & Richard Yu Peritoneal Dialysis Research Centre, Departments of Medicine & Therapeutics, Prince of Wales Hospital.
Li Ka Shing Institute of Health Sciences (LiHS), Faculty of Medicine, The Chinese University of Hong Kong, Shatin, Hong Kong, China.
Clin Kidney J. 2024 Sep 30;17(10):sfae297. doi: 10.1093/ckj/sfae297. eCollection 2024 Oct.
Sarcopenia is common in peritoneal dialysis (PD) patients. Modified creatinine index (MCrI) by the Canaud's formula and single-pool Kt/V value is an accurate surrogate marker for muscle mass in hemodialysis patients. However, the method of calculation and validity of MCrI has not been tested in PD.
In the exploratory cohort, we studied 138 consecutive patients converted from PD to hemodialysis. Their MCrI during PD, calculated by the Canaud's formula with total weekly Kt/V, and the conventional MCrI after conversion to HD, were compared by the Bland-Altman method. Their correlation with muscle mass as determined by bioimpedance spectroscopy and creatinine kinetic methods was explored. The result was then validated in a second cohort of 605 incident PD patients.
In the exploratory cohort, the average bias of computing MCrI during PD and hemodialysis was 0.758 mg/kg/day (95%CI -4.356 to 5.873 mg/kg/day). The MCrI during PD significantly correlated with the muscle mass by creatinine kinetics ( = .684, < .0001) and by bioimpedance spectroscopy ( = .641, < .0001), but not with protein nitrogen appearance, overhydration, or adipose tissue mass, and the result was similar in the validation cohort. For incident PD patients, MCrI quartile was significantly associated with the risk of death from all cause in 12 months (Gray's test, = .013) but not conversion to chronic hemodialysis ( = .14).
In PD patients, MCrI computed by the Canaud's formula and total weekly Kt/V is a simple and reliable marker of skeletal muscle mass and may serve as a short-term prognostic indicator.
肌肉减少症在腹膜透析（PD）患者中很常见。通过Canaud公式计算的改良肌酐指数（MCrI）和单池Kt/V值是血液透析患者肌肉质量的准确替代指标。然而，MCrI的计算方法和有效性尚未在PD中得到验证。
在探索性队列中，我们研究了138例从PD转为血液透析的连续患者。通过Bland-Altman方法比较了他们在PD期间通过Canaud公式与每周总Kt/V计算的MCrI，以及转为HD后的传统MCrI。探讨了它们与通过生物电阻抗光谱法和肌酐动力学方法测定的肌肉质量的相关性。然后在605例新发PD患者的第二个队列中验证了结果。
在探索性队列中，PD和血液透析期间计算MCrI的平均偏差为0.758mg/kg/天（95%CI -4.356至5.873mg/kg/天）。PD期间的MCrI与肌酐动力学（r = 0.684，P < 0.0001）和生物电阻抗光谱法（r = 0.641，P < 0.0001）测定的肌肉质量显著相关，但与蛋白质氮出现、水钠潴留或脂肪组织质量无关，在验证队列中结果相似。对于新发PD患者，MCrI四分位数与12个月内全因死亡风险显著相关（Gray检验，P = 0.013），但与转为慢性血液透析无关（P = 0.14）。
在PD患者中，通过Canaud公式和每周总Kt/V计算的MCrI是骨骼肌质量的简单可靠指标，可作为短期预后指标。
