P1200peritoneal Protein Losses: What Do We Mean

Abstract

Background and Aims The report of peritoneal protein loss should be related with a timely collection (24-hour measurement or 4-hour PET assessment) or concentration. Standardized and reproducible estimation of peritoneal protein transport is obtained during PET. The 24-hour measurements estimate the real amount of PPL, but may be affected by other factors unrelated to the prognosis of PD patients, as inconsistencies in collection and management of the samples. Overall, PET protein loss quantification may be a more specific marker of peritoneal large-pore dysfunction and is seemingly more convenient than 24-hour measurements. The aim of this study was to compare the results of both sampling methods. Method A total of 144 adult incident PD patients were included. A standard peritoneal equilibration test, 24-hour urine and dialysate collection, and multifrequency bioimpedance analysis were performed. Independent-samples t test and Pearson correlation coefficient were performed to evaluate relevant clinical associations. Results Statistically significant univariable relationships for 24h PPL were found for continuous ambulatory PD technique (CAPD) and, with a correlation coefficient >0.20, for pulse pressure, 4-hour dialysate/plasma creatinine and extracellular water/total body water. Studying 240 min PPL, only with 4-hour dialysate/plasma creatinine, creatinine clearance and bicarbonate levels were statistically significant. In both samples there was no significant association with age, gender, type of effluent (biocompatible solutions or lactate plus bicarbonate comparing with bicarbonate), comorbidity Charlson Index, or presence of diabetes. Correlation between 240 min PPL and 24h PPL ensues, but it is not strong (p<0.001; r=0.365). Conclusion The weak correlation between 24h and 240 minutes show that these two measurements should not be considered equivalent. Measurements of a 24h sample might be more close to patients’ clinical status and prognosis, despite more frequent sampling errors. PET protein loss quantification should be regarded as a marker of peritoneal large-pore dysfunction.