De novo Hyponatremia in Patients Undergoing Peritoneal Dialysis: A 12-month Observational Study

Lee, Hyun Hee; Choi, Soo Jung; Lee, Heon Nam; Na, Sun Young; Chang, Jae Hyun; Chung, Wookyung; Kim, Sejoong

Abstract

PURPOSE
Hyponatremia occurs infrequently in patients undergoing peritoneal dialysis (PD). Nevertheless, one must understand its pathophysiology, since the therapeutic strategy differs from that of non- PD-related hyponatremia. This study examined the clinical features of hyponatremia in PD and evaluated the factors that may contribute to its development.
METHODS
We retrospectively enrolled 51 normonatremic PD patients at Gachon University Gil Hospital, South Korea. Using the plasma sodium levels at month 13, the patients were divided into hyponatremia (Na+ <135 mEq/L) and normonatremia (Na+ > or = 135 mEq/L) groups. Then, the clinical variables of these patients were examined, including peritoneal function and adequacy tests, and biochemical parameters.
RESULTS
The de novo hyponatremia (n=8) and normonatremia (n=43) groups had no significant differences in baseline characteristics. At month 1, the serum albumin was lower in the hyponatremia group (p=0.022). In the peritoneal equilibration test analysis, the dialysate-to-plasma ratio for creatinine (D/ P(Cr)) measured after 13 months differed significantly between the two groups (p=0.007), while the maximum dip in sodium did not differ. No significant differences were observed in the normalized protein equivalent of nitrogen appearance, Kt/V, or residual renal function.
CONCLUSION
Our data suggest that the development of hyponatremia is associated with a lower initial serum albumin level and increased D/P(Cr) in patients undergoing PD. Therefore, the serum sodium levels should be monitored more carefully in these patients.