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Kidney Week

Abstract: PO0469

Metabolic Acidosis Is Associated with CKD Progression: A Longitudinal Analysis of >100,000 US Community-Based Patients

Session Information

Category: CKD (Non-Dialysis)

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

Authors

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

To delay the progression of CKD, it is imperative to identify modifiable risk factors and then to evaluate efficacy of interventions. Here we assess the role of metabolic acidosis as an independent risk factor for CKD progression in patients (pts) with non-dialysis-dependent CKD Stages 3-5.

Methods

De-identified electronic medical records (Optum® EMR), 2007–2019 were queried to identify pts with non-dialysis CKD Stages 3-5, (2 consecutive eGFR values >10 and <60 mL/min/1.73m2 90-365 days apart) followed by 2 consecutive serum bicarbonate values 28–365 days apart, both 12 to <22 mEq/L (metabolic acidosis) or 22 to <30 mEq/L (normal serum bicarbonate) and ≥2 yrs of post-index data or death within 2 yrs. Pts (N = 136,067) were followed for up to 11.5 yrs for evidence of CKD progression, measured as a ≥40% decline in eGFR from baseline and as progression of ≥ 1 CKD stage from baseline using laboratory data. We describe outcomes at 2 yrs and used Cox proportional hazards models over the entire follow-up period to examine potential confounders: age, sex, race/ethnicity, eGFR, log albumin-creatinine ratio, diabetes, hypertension, heart failure, and weighted Charlson Comorbidity Index.

Results

75,127 pts (55%) progressed 1 or more CKD stages within 2 yrs. The incidence of CKD progression within 2 years was significantly higher in pts with metabolic acidosis compared to pts with normal serum bicarbonate, irrespective of the endpoint (≥40% decline in eGFR: 38.3% vs. 20.4%, P< 0.0001; progression of ≥ 1 CKD stage: 66.7% vs. 54.5%, P< 0.0001). During the up to 11.5-yrs of follow-up (median 4.2 yrs), serum bicarbonate was independently associated with CKD progression; hazard ratios per 1 mEq/L increase in serum bicarbonate were 0.969, CI: 0.965-0.973 for a ≥40% decline in eGFR and 0.975, CI: 0.972-0.977 for progression ≥1 CKD stage.

Conclusion

In pts with non-dialysis CKD, serum bicarbonate levels below 22 mEq/L were independently associated with increased risk of CKD progression. Large randomized trials targeting treatment of metabolic acidosis to slow CKD progression are needed. There was a 2.5–3.0% risk reduction for a ≥40% decrease in eGFR or progression by ≥1 CKD stage for every 1 mEq/L increase in serum bicarbonate.

Funding

  • Commercial Support