Comparison of three PET methods to assess peritoneal membrane transport

The peritoneal equilibration test (PET) is the most widespread method for assessing water and solute transport across the peritoneal membrane. This study compared three methods: traditional PET (t-PET), mini-PET, and modified PET (mod-PET). Non-diabetic adults (n=21) who had been on peritoneal dialysis (PD) for at least three months underwent t-PET (glucose 2.5%-4 h), mini-PET (glucose 3.86%-1 h), and mod-PET (glucose 3.86%-4 h) to determine dialysate-to-plasma concentration ratio (D/P) for creatinine and dialysate-to-baseline dialysate concentration ratio (D/D0) for glucose. Agreement between methods regarding D/P creatinine and D/D0 glucose was assessed using analysis of variance (ANOVA), Pearson's correlation coefficient, and Bland-Altman analysis. D/P creatinine differed between t-PET and mini-PET (P<0.001) and between mod-PET and mini-PET (P<0.01) but not between t-PET and mod-PET (P=0.746). The correlation of D/P creatinine with t-PET vs mod-PET was significant (r=0.387, P=0.009) but not that of t-PET vs mini-PET (r=0.088, P=0.241). Estimated bias was −0.029 (P=0.201) between t-PET and mod-PET, and 0.206 (P<0.001) between t-PET and mini-PET. D/D0 glucose differed between t-PET and mod-PET (P=0.003) and between mod-PET and mini-PET (P=0.002) but not between t-PET and mini-PET (P=0.885). The correlations of D/D0 glucose in t-PET vs mod-PET (r=−0.017, P=0.421) or t-PET vs mini-PET (r=0.152, P=0.609) were not significant. Estimated bias was 0.122 (P=0.026) between t-PET and mod-PET, and 0.122 (P=0.026) between t-PET and mini-PET. The significant correlation of D/P creatinine between t-PET and mod-PET suggested that the latter is a good alternative to t-PET. There was no such correlation between t-PET and mini-PET.

腹膜平衡试验（peritoneal equilibration test, PET）是目前评估腹膜跨膜水和溶质转运最广泛应用的方法。本研究对比了三种检测方法：传统腹膜平衡试验（traditional PET, t-PET）、迷你腹膜平衡试验（mini-PET）以及改良式腹膜平衡试验（modified PET, mod-PET）。招募21例已接受腹膜透析（peritoneal dialysis, PD）至少3个月的非糖尿病成人，分别采用t-PET（葡萄糖浓度2.5%，检测时长4小时）、mini-PET（葡萄糖浓度3.86%，检测时长1小时）以及mod-PET（葡萄糖浓度3.86%，检测时长4小时）进行检测，以测定肌酐的透析液-血浆浓度比（dialysate-to-plasma concentration ratio, D/P）与葡萄糖的透析液-基线透析液浓度比（dialysate-to-baseline dialysate concentration ratio, D/D0）。采用方差分析（analysis of variance, ANOVA）、皮尔逊相关系数以及布兰德-奥特曼分析，评估三种检测方法在肌酐D/P值与葡萄糖D/D0值上的一致性。肌酐D/P值在t-PET与mini-PET组间存在显著差异（P<0.001），mod-PET与mini-PET组间同样存在显著差异（P<0.01），但t-PET与mod-PET组间无显著差异（P=0.746）。肌酐D/P值在t-PET与mod-PET组间的相关性具有统计学意义（r=0.387，P=0.009），但t-PET与mini-PET组间的相关性无统计学意义（r=0.088，P=0.241）。t-PET与mod-PET组间的估计偏倚为-0.029（P=0.201），t-PET与mini-PET组间的估计偏倚为0.206（P<0.001）。葡萄糖D/D0值在t-PET与mod-PET组间存在显著差异（P=0.003），mod-PET与mini-PET组间同样存在显著差异（P=0.002），但t-PET与mini-PET组间无显著差异（P=0.885）。葡萄糖D/D0值在t-PET与mod-PET组间（r=-0.017，P=0.421）以及t-PET与mini-PET组间（r=0.152，P=0.609）的相关性均无统计学意义。t-PET与mod-PET组间的估计偏倚为0.122（P=0.026），t-PET与mini-PET组间的估计偏倚同样为0.122（P=0.026）。肌酐D/P值在t-PET与mod-PET组间的显著相关性提示，mod-PET可作为t-PET的优良替代方案；而t-PET与mini-PET组间未发现此类相关性。