The Beneficial Effect of Oral Sodium Bicarbonate in Peritoneal Dialysis Patients — How Long Does It Last After Stopping Treatment?

Background

Acidosis is a major feature of progressive malnutrition in dialysis patients. Our previous study showed that in peritoneal dialysis (PD) patients with mild acidosis, oral sodium bicarbonate improved nutritional status and reduced hospitalization. However, the required duration of bicarbonate treatment remains unknown. Methods: Patients who participated in our previously reported randomized, controlled study of sodium bicarbonate therapy (J Am Soc Nephrol 2003;14:2119-26) were followed for another 12 months after treatment was stopped. We compared the two groups (i.e. sodium bicarbonate therapy vs placebo) with regard to nutritional status, including subjective global assessment (SGA) score and normalized protein nitrogen appearance (NPNA), and hospitalization and mortality.

Results

In the treatment group, the overall SGA score tended to fall to the pretreatment level 12 months after bicarbonate therapy was stopped (5.15 ± 1.04 to 4.68 ± 0.99, p = 0.08). After 12 months, there was no difference in overall SGA score between the treatment and placebo groups (4.68 ± 0.99 vs 4.58 ± 1.10, p = 0.5). NPNA of the treatment group remained marginally higher than that of the placebo group (1.21 ± 0.49 vs 1.06 ± 0.49 g/kg/day, p = 0.21), although the difference was not statistically significant. There was no significant difference in the duration of hospitalization between groups after bicarbonate was stopped (12.3 ± 19.9 vs 16.9 ± 23.7 days/year; Kruskal-Wallis test, p = 0.31). The treatment group had a slightly higher actuarial patient survival (83.3% vs 76.7%; log-rank test, p = 0.22), but the difference was not statistically significant.

Conclusion

The therapeutic benefits of oral sodium bicarbonate disappeared rapidly when treatment was stopped. Our results suggest that oral sodium bicarbonate is beneficial in PD patients with borderline dialysis adequacy and mild metabolic acidosis, and that these patients require long-term bicarbonate treatment.

Key words:  continuous ambulatory peritoneal dialysis , metabolic acidosis , mortality , nutritional status , sodium bicarbonate

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