The peritoneal sieving of sodium: a simple and powerful test to rule out the onset of encapsulating peritoneal sclerosis in patients undergoing peritoneal dialysis.

Abstract

Encapsulating peritoneal sclerosis (EPS) is an uncommon but severe complication of peritoneal dialysis (PD). A reliable screening tool to identify patients at risk of developing or not EPS is currently not available. We aimed to evaluate whether the reduction in dialysate sodium concentration (sodium sieving) at 60min (ΔDNa60), during a peritoneal equilibration test with 3.86% glucose concentration (3.86%-PET) was able to early rule out patients who will not develop EPS. Prospective controlled longitudinal (20-year) cohort study. All eligible incident PD patients attending the hospital underwent a 3.86%-PET during the first 3 months following start of PD and then once a year. The dip in ΔDNa60 and other factors were correlated with eventual EPS onset. Of 161 incident PD patients, with a median PD duration of 37.8 (24.7-58.3) months and 64.1 (34.5-108.3) months of follow-up, 13 patients (8%) developed EPS at a median PD duration of 72.7 (56.6-109.4) months and 105.0 (76.4-143.2) months of follow-up. ΔDNa60 demonstrated the best sensitivity and specificity values, estimated by conventional receiver operating characteristic (ROC) curve analysis with an area under the curve (AUC) of 0.90, 0.83 and 0.85 at 1, 2 and 3 years before the onset of EPS, respectively. Multifactorial analysis showed that the most useful factors for predicting EPS were age at start of PD, duration of PD, small solutes transport (D/PCreat) and ΔDNa60; the AUC at 1, 2 and 3 years before the onset of EPS was, respectively, 0.97, 0.96 and 0.94, the positive predictive value being 0.48, 0.57 and 0.42, and the negative predictive value 1.0, 1.0 and 1.0. It is possible to predict the occurrence and, better, the non-occurrence of EPS using simple parameters such as age at PD start, duration of PD, and parameters obtained by 3.86%-PET such as D/PCreat and ΔDNa60.