Long-term stability of serum sodium in hemodialysis patients.

BACKGROUND

A direct relationship between dialysate-to-plasma sodium gradient, blood pressure and interdialytic weight gain exists in hemodialysis (HD) patients. The aim of this study was to delineate the long-term variability of serum sodium in HD patients.

METHODS

We performed a retrospective cohort analysis of serum sodium and other analytes routinely evaluated in 100 stable chronic HD patients observed for 12 months.

RESULTS

Individual levels across the cohort varied from 122 to 145 m M , but 12-month intraindividual coefficients of variation for sodium were low (pre-HD = 1.6%; post-HD = 1.8%) with overall variability similar to that related to laboratory assay variability especially when compared with other analytes (3.1-30.8%). Pre-HD serum sodium had a trend toward hyponatremia (mean 136 +/- 0.8 m M ).

CONCLUSION

Serum sodium is stable over time in HD patients. Pre-HD serum sodium may be used as a parameter for individualizing dialysate sodium prescription.