Low Sodium Dialysate Trial Links Treatment To Tissue Sodium Shifts

Key Takeaways

• A randomized crossover trial compared low-sodium and higher-sodium dialysate in maintenance hemodialysis, and overall muscle and skin sodium differences were not statistically significant.
• After adjustment, low-sodium dialysate was associated with lower skin sodium but not muscle sodium, while higher ultrafiltration rate was associated with lower sodium in both compartments.
• hsCRP and prealbumin were not significantly different between periods, and no serious study-related adverse events were reported.

In a randomized crossover trial in maintenance hemodialysis, 132 mEq/L and 138 mEq/L dialysate produced no statistically significant overall differences in skin or muscle sodium after two 4-week treatment periods. Tissue sodium was measured with 23Na magnetic resonance imaging at the end of each period, and 23 of 28 randomized participants completed both treatments.

The study enrolled patients receiving maintenance hemodialysis and assigned them to initial treatment with low-sodium dialysate at 132 mEq/L or higher-sodium dialysate at 138 mEq/L. Each treatment lasted four weeks, and tissue sodium was assessed with 23Na magnetic resonance imaging at the end of both periods. Twenty-eight participants entered randomization, and 23 contributed data from both treatment phases for the crossover analysis. Skin sodium and muscle sodium were the two tissue compartments assessed with imaging.

Using high-sodium dialysate as the reference period, investigators estimated a least-squares mean treatment difference of -0.8 for muscle sodium and -1.5 for skin sodium during low-sodium dialysate exposure. These overall differences were not statistically significant, with p=0.27 for muscle sodium and p=0.09 for skin sodium. Both compartments trended lower during low-sodium exposure, but the reported p values remained above conventional significance thresholds. Adjusted models provided a separate analysis of the same data.

In models adjusted for baseline tissue sodium and ultrafiltration rate, low-sodium dialysate was associated with decreased skin sodium. The same adjusted analyses did not link low-sodium dialysate with decreased muscle sodium. Higher ultrafiltration rate was significantly associated with lower sodium in both skin and muscle. These findings separated skin from muscle for dialysate sodium, while ultrafiltration was associated with both compartments.

High-sensitivity C-reactive protein and prealbumin did not differ significantly between treatment periods, with no clear systemic separation between the dialysate regimens. No serious study-related adverse event occurred during either treatment period. Safety findings were similar across the two periods in this crossover sample. The authors interpreted the findings as suggesting that dialysate sodium concentration and ultrafiltration rate may modify tissue sodium. They also noted that larger studies are needed to assess these effects and related clinical outcomes.