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Abstract: FR-OR058

Effects of Different Serum Bicarbonate Levels on Muscle Mass and Renal Function Among CKD Patients with Metabolic Acidosis: A Randomized Controlled Trial

Session Information

Category: Health Maintenance, Nutrition, and Metabolism

  • 1300 Health Maintenance, Nutrition, and Metabolism

Authors

  • Srijaruneruang, Somrath, Chulalongkorn, Bangkok, Thailand
  • Kittiskulnam, Piyawan, Chulalongkorn university , Bangkok, Thailand
  • Praditpornsilpa, Kearkiat, Chulalongkorn University, Bangkok, Thailand
  • Eiam-Ong, Somchai, Chulalongkorn University, Bangkok, Thailand
Background

Treatment of metabolic acidosis to target high serum bicarbonate level may downregulate muscle protein degradation and retard GFR decline among CKD patients. We conducted a study to test the effects of increased bicarbonate level on muscle parameters and renal function in pre-dialysis CKD patients.

Methods

This was a randomized, controlled study. CKD stage 3-4 patients with serum HCO3-<22 mmol/L were randomized to either receive oral sodium bicarbonate with target bicarbonate level of 25±1 or standard level of 22±1 mmol/L as control group using the protocol-based titration of dosage adjustment. The change of muscle mass measured by bioelectrical impedance analysis (BIA), muscle strength by hand grip dynamometer, eGFR using CKD-EPI equation, nutritional markers, and muscle-related biomarkers were determined. Baseline data and after 6 months of sodium bicarbonate supplementation were compared between groups using t-test or Chi-square test as appropriate.

Results

Forty-two patients completed the study (n=21 per group). The mean age and eGFR were 61.2±9.8 years and 32.4±14.1 ml/min, respectively. Baseline data including age, sex, diabetes, serum bicarbonate level, muscle mass, and blood pressure were similar. After 6 months of treatment, the average serum bicarbonate levels in both group were 24.8 and 21.2 mmol/L. Both BIA-derived total-body muscle mass and appendicular lean balance were significantly increased at 6 months in the higher bicarbonate group (26.0±5.4 to 26.7±5.7 kg, p=0.04 and 19.8±4.1 to 20.6±4.5 kg, p=0.03, respectively) despite comparable energy and protein intake. The higher bicarbonate group also had 36% lower serum myostatin, a surrogate for muscle degradation, but unaltered insulin-like growth factor-1 level as the mediator of muscle cell growth (133.8±43.6 vs 121.3±52.7 ng/mL, p=0.3) compared to the control group. Muscle strength, eGFR as well as serum albumin were not significantly different between two groups (p>0.05). Neither worsening hypertension nor heart failure was found throughout the study.

Conclusion

Bicarbonate supplementation to achieve the serum level ~25 mmol/L demonstrates better muscle mass preservation in patients with pre-dialysis CKD. The impact of alkaline therapy on renal function may require longer period of study.

Funding

  • Government Support - Non-U.S.