Abstract
A consistent association between low serum sodium measured at a single-point-in-time (baseline sodium) and higher mortality has been observed in hemodialysis patients. We hypothesized that both low and high time-varying sodium levels (sodium levels updated at quarterly intervals as a proxy of short-term exposure) are independently associated with higher death risk in hemodialysis patients. We examined the association of baseline and time-varying pre-dialysis serum sodium levels with all-cause mortality among adult incident hemodialysis patients receiving care from a large national dialysis organization during January 2007-December 2011. Hazard ratios were estimated using multivariable Cox models accounting for case-mix+laboratory covariates and incrementally adjusted for inter-dialytic weight gain, blood urea nitrogen and glucose. Among 27 180 patients, a total of 7562 deaths were observed during 46 194 patient-years of follow-up. Median (IQR) at-risk time was 1.4 (0.6, 2.5) years. In baseline analyses adjusted for case-mix+laboratory results, sodium levels <138 mEq/L were associated with incrementally higher mortality risk, while the association of sodium levels ≥140 mEq/L with lower mortality reached statistical significance only for the highest level of pre-dialysis sodium (reference: 138-<140 mEq/L). In time-varying analyses, we observed a U-shaped association between sodium and mortality such that sodium levels <138 and ≥144 mEq/L were associated with higher mortality risk. Similar patterns were observed in models incrementally adjusted for inter-dialytic weight gain, blood urea nitrogen and glucose. We observed a U-shaped association of time-varying pre-dialysis serum sodium and all-cause mortality in hemodialysis patients, suggesting that both hypo- and hypernatremia carry short-term risk in this population.
Highlights
Dysnatremias are the most common electrolyte disorder encountered in clinical practice, and are disproportionately observed across a variety of medical conditions, including chronic kidney disease (CKD) [1,2,3]
We observed a U-shaped association of timevarying pre-dialysis serum sodium and all-cause mortality in hemodialysis patients, suggesting that both hypo- and hypernatremia carry short-term risk in this population
In a recent study examining time-varying sodium levels in CKD patients not undergoing maintenance dialysis, both hypo- and hypernatremia were associated with higher mortality risk [3, 14]
Summary
Dysnatremias are the most common electrolyte disorder encountered in clinical practice, and are disproportionately observed across a variety of medical conditions, including chronic kidney disease (CKD) [1,2,3]. While high serum sodium has been associated with higher death risk in non-CKD patients [12, 13], the association of hypernatremia with all-cause mortality has not previously been reported in studies of hemodialysis patients. In a recent study examining time-varying sodium levels (i.e. sodium levels updated at quarterly intervals, as a proxy of short-term exposure) in CKD patients not undergoing maintenance dialysis, both hypo- and hypernatremia were associated with higher mortality risk [3, 14]. A consistent association between low serum sodium measured at a single-point-in-time (baseline sodium) and higher mortality has been observed in hemodialysis patients We hypothesized that both low and high time-varying sodium levels (sodium levels updated at quarterly intervals as a proxy of short-term exposure) are independently associated with higher death risk in hemodialysis patients. Similar patterns were observed in models incrementally adjusted for inter-dialytic weight gain, blood urea nitrogen and glucose
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
