Kidney Week

Abstract: PO0467

Metabolic Acidosis and Progression to Renal Replacement Therapy

Session Information

• CKD Risk Factors: Diet, Environment, Lifestyle
  October 22, 2020 | Location: On-Demand
  Abstract Time: 10:00 AM - 12:00 PM

Category: CKD (Non-Dialysis)

• 2101 CKD (Non-Dialysis): Epidemiology, Risk Factors, and Prevention

Authors

• Mathur, Vandana S., MathurConsulting, Woodside, California, United States

Vandana S. Mathur,

• Funk, Susan E., Strategic Health Resources, La Canada, California, United States

Susan E. Funk,

• Reaven, Nancy L., Strategic Health Resources, La Canada, California, United States

Nancy L. Reaven,

• Tangri, Navdeep, University of Manitoba, Winnipeg, Manitoba, Canada

Navdeep Tangri,

Background

Metabolic acidosis is common in advanced chronic kidney disease (CKD) and is associated with its progression (Kraut J, Adv Chronic Kidney Dis. 2017).

Methods

De-identified electronic health records (Optum^® EHR), 2007 to 2017 were queried to identify patients with non-dialysis CKD Stages 3-5 with ≥2 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 index serum bicarbonate (< 22 mEq/L or 22 - 29 mEq/L). Progression to RRT was defined as initiation of dialysis or kidney transplantation, identified in EHR data by diagnosis or procedure codes, or eGFR ≤ 9 mL/min/1.73 m². We evaluated the impact of baseline serum bicarbonate on RRT initiation, 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) using logistic regression models (2-year outcome period) and Cox proportional hazards models (up to 10 years).

Results

51,558 patients qualified for analysis; 17,350 with metabolic acidosis, 34,208 with normal serum bicarbonate at baseline. Unadjusted rates of progression to RRT within 2 years were higher among patients with metabolic acidosis vs. normal serum bicarbonate overall (19.6% vs. 5.5%, respectively, p< 0.001) and at all baseline CKD stages (p< 0.001) except stage 5 (p=0.4). Each 1 mEq/L increase in serum bicarbonate between 12 and 29 mEq/L was associated with a 2.5% decrease in the 2-year risk of initiating RRT, (OR: 0.975, 95% CI: 0.965, 0.985), and a 4.5% decrease in risk up to 10 years (HR: 0.955, 95% CI: 0.948, 0.963).

Conclusion

The presence of metabolic acidosis was associated with an increased risk of CKD progression to dialysis or kidney transplantation. This finding was independent of age, sex, race, pre-existing comorbidities, and baseline eGFR and ACR.

Funding

• Commercial Support –