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Abstract: FR-PO274

Metabolic Acidosis Is an Independent Predictor of Adverse Renal Outcomes and Higher Costs in Patients with CKD

Session Information

Category: CKD (Non-Dialysis)

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

Authors

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

Metabolic acidosis (MA) is a risk factor for chronic kidney disease (CKD) progression, but less is known about its effect on health care costs and resource utilization. We describe the association between MA, adverse renal outcomes and costs in non-dialysis patients with CKD stages 3-5.

Methods

De-identified medical records (Optum® EMR), 2007–2017 were used to identify non-dialysis CKD patients with ≥2 serum bicarbonate test values 28–365 days apart, ≥3 eGFR values >10 and <60 mL/min/1.73m2 and ≥2 years of post-index data or death. Patients were followed for 2 years for the composite outcome (DD40) of death, dialysis, renal transplant, or eGFR decline ≥40%. Metabolic acidosis and normal serum bicarbonate groups were defined by 2 serum bicarbonate values between 12 and <22 mEq/L and 22–29 mEq/L, respectively. General linear regression models in a subset of patients with linked medical claims established predicted costs, which were applied to the larger EMR population based on demographic and clinical factors. Logistic and generalized linear regression models assessed serum bicarbonate as a predictor of DD40 outcomes and costs (log) respectively, controlling for age, sex, race, eGFR, log albumin-to-creatinine ratio, diabetes, hypertension, heart failure, and Charlson comorbidity score.

Results

51,558 patients qualified for this longitudinal observational study. Compared to patients with normal serum bicarbonate, patients with MA experienced CKD progression at much higher rates, (DD40 rates 48% vs. 17%, p<0.0001) and significantly higher per patient per year costs, ($65,152 vs. $24,681, p<0.0001). This pattern was consistent across all stages of CKD, except stage 5. Serum bicarbonate independently predicted DD40 events and costs; odds ratio of CKD progression (DD40) for each 1 mEq/L increase in serum bicarbonate was 0.87, (CI: 0.866-0.879); parameter estimate -0.076 (p<0.0001) for costs.

Conclusion

In this analysis of >51,000 non-dialysis CKD patients followed for two years, patients with metabolic acidosis had higher rates of adverse renal outcomes and higher costs compared to patients with normal serum bicarbonate. Each 1 mEq/L increase in serum bicarbonate was associated with a 13% decrease in 2-year DD40 events and a 7% decrease in monthly costs.

Funding

  • Commercial Support