Preservation of residual renal function with limited water removal in hemodialysis patients

Residual renal function (RRF) is of paramount importance for hemodialysis (HD) adequacy, morbidity, and mortality. Some studies have shown that overhydration is beneficial for preservation of RRF, but it can also increase the probability of adverse events such as hypertension and heart failure in HD patients. To determine the optimal amount of dehydration, we performed HD with limited water removal in HD patients. Eighteen HD patients included in this self-controlled study underwent HD with limited water removal. Water removal volume was determined by a previous volume as follows. Total water removal volume was divided into levels: ≤3.0, 3.0-9.0, and >9.0 L per week. Water removal was performed to obtain dry weight in the last dialysis, and was performed three times with a ratio of 1:1:2 and 2:2:3, respectively. Urine volume, endogenous creatinine clearance rate, Kt/V, hemoglobin, and serum albumin were recorded before and after the study at 3, 6, 9, and 12 months. The follow-up period was 12 months. Ten patients withdrew from the study because of adverse events including hypertension (n = 3), heart failure (n = 3), angina (n = 1), polycystic kidney rupture (n = 1), obvious edema (n = 1), and one patient had too much interdialytic weight gain to continue. As a result, we stopped this study after 1 month. Our data suggest that the preservation of RRF with limited water removal in HD patients must be interpreted with caution.