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Abstract: PO1483

Metabolic Acidosis Is a Predictive Factor for All-Cause Mortality in Patients with CKD

Session Information

Category: Fluid, Electrolyte, and Acid-Base Disorders

  • 902 Fluid, Electrolyte, and Acid-Base Disorders: Clinical

Authors

  • Tangri, Navdeep, University of Manitoba, Winnipeg, Manitoba, Canada
  • Reaven, Nancy L., Strategic Health Resources, La Canada, California, United States
  • Funk, Susan E., Strategic Health Resources, La Canada, California, United States
  • Mathur, Vandana S., MathurConsulting, Woodside, California, United States
Background

The consequences of metabolic acidosis are wide-ranging, consistent with the fact that many critical cell functions require physiologic pH (Salameh AI, Am J Physiol Regul Integr Comp Physiol. 2014). The extent to which metabolic acidosis contributes to mortality in patients with chronic kidney disease (CKD) is unknown.

Methods

Optum® de-identified Electronic Health Records dataset 2007 to 2017 was queried to identify patients with non-dialysis CKD Stages 3-5 with ≥2 consistent serum bicarbonate tests 28–365 days apart, ≥3 eGFR values <60 mL/min/1.73 m2 and ≥2 years of post-index data or who died during that period. Cohorts with metabolic acidosis and normal serum bicarbonate were established based on the baseline serum bicarbonate (12 to < 22 mEq/L or 22 - 29 mEq/L). All-cause mortality was measured at 2 years in patients with metabolic acidosis vs. normal serum bicarbonate at baseline. The impact of baseline serum bicarbonate on 2-year mortality, adjusted for age, sex, race, diabetes, hypertension, heart failure, Charlson Comorbidity Score (index of comorbidity burden), and baseline eGFR and log albumin-to-creatinine ratio (ACR) was evaluated using logistic regression models.

Results

51,558 patients qualified for analysis; 17,350 with metabolic acidosis, 34,208 with normal serum bicarbonate at baseline. Unadjusted rates of mortality within 2 years were higher among patients with metabolic acidosis vs. normal serum bicarbonate (30.9% vs. 10.2%, respectively, P< 0.0001) and within all CKD stages (P< 0.001). Each 1 mEq/L lower serum bicarbonate value was independently associated with a 15% higher risk of all-cause mortality, OR: 0.853, 95% CI: 0.846-0.861. These findings were consistent in subgroup and sensitivity analyses.

Conclusion

The presence of metabolic acidosis was associated with a high 2-year risk of all-cause death in patients with CKD. This finding was independent of age, sex, race, pre-existing comorbidities, and baseline eGFR and ACR.

Funding

  • Commercial Support