Simple method to estimate daily sodium intake during measurement of dialysis adequacy in chronic peritoneal dialysis patients.

BACKGROUND AND OBJECTIVES Restriction of dietary sodium intake for peritoneal dialysis (PD) patients is recommended, but there is limited information on the measurement and monitoring of sodium intake. We have developed a simple method to estimate daily sodium intake during the measurement of dialysis adequacy in PD patients. METHODS AND STUDY DESIGN A total of 83 PD patients were enrolled in the study. The patients were divided into two groups based on residual renal function (RRF). We measured total sodium removal and estimated daily sodium intake using dietary recall for one day, during the assessment of dialysis adequacy. RESULTS There were 39 patients in the RRF(-) group and 44 in the RRF(+) group. In both groups, and all patients, there were significant positive correlations between sodium intake and total sodium removal: RRF(-) group, r=0.598; RRF(+) group, r=0.577; total patients, r=0.595. There were linear relationships between dietary sodium intake and total sodium removal in both groups: RRF(-) group, sodium intake (mg/d) = 19.3 × peritoneal sodium removal (mEq/d) + 211;RRF(+) group, sodium intake (mg/d) = 15.4 × total sodium removal (mEq/d) + 609. All PD patients, sodium intake (mg/d) = 15.6 × total sodium removal (mEq/d) + 646. CONCLUSIONS The measurement of total sodium removal during the assessment of dialysis adequacy could be an effective and simple method to estimate dietary sodium intake in PD patients. A dietary intake of 2,000 mg of sodium corresponds to a total sodium removal of approximately 87 mEq/d.