Ratio of Urinary Potassium to Urinary Sodium and the Potassium and Edema Status in Nephrotic Syndrome

Objective This study aimed to evaluate the relevance of ratios of urinary potassium to urinary sodium + potassium (UK/UNa + K) to edema status in minimal-change nephrotic syndrome (MCNS). Methods We retrospectively studied 26 adults with newly diagnosed MCNS with significant pitting edema. On the basis of mean value (0.46±0.21) of UK/UNa + K determined from spot urine samples on admission, patients were classified into 2 groups. Results On admission, 12 of 26 patients had UK/UNa + K >0.46 (0.65±0.16, Group H), 14 patients had UK/UNa + K <0.46 (0.29±0.08, Group L). The level of serum albumin was similarly decreased in these 2 groups. Noteworthy were lower urine volume, fractional excretion of sodium (FENa), serum sodium, and higher hematocrit in the group H as compared with the group L. The group H had a shorter mean time required from onset of edema to hospitalization, and tended to have a longer mean time to complete remission than group L. High UK/UNa + K levels in group H decreased significantly after remission, eventually becoming equal to those of group L (0.24±0.05 vs. 0.25±0.05). Conclusion UK/UNa + K determined from spot urine sample on admission relates to laboratory or clinical indices to distinguish edema status in adult patients with MCNS.