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Kidney Week

Abstract: FR-PO275

Association of Total CO2 Levels with Albuminuria Progression in Patients with CKD: Results from the KNOW CKD Cohort

Session Information

Category: CKD (Non-Dialysis)

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

Authors

  • Kim, Kipyo, Seoul National University Bundang Hospital, Gyeonggi-do, Korea (the Republic of)
  • Yi, Yongjin, Seoul National University Bundang Hospital, Gyeonggi-do, Korea (the Republic of)
  • Jeong, Jong Cheol, Seoul National University Bundang Hospital, Gyeonggi-do, Korea (the Republic of)
  • Kim, Sejoong, Seoul National University Bundang Hospital, Gyeonggi-do, Korea (the Republic of)
  • Chin, Ho Jun, Seoul National University Bundang Hospital, Gyeonggi-do, Korea (the Republic of)
  • Na, Ki Young, Seoul National University Bundang Hospital, Gyeonggi-do, Korea (the Republic of)
  • Chae, Dong-Wan, Seoul National University Bundang Hospital, Gyeonggi-do, Korea (the Republic of)
Background

Metabolic acidosis is a common manifestation of CKD and contributes to various adverse effects. Although previous animal studies demonstrated that dietary acid induces an increase in proteinuria, the association between total CO2 and albuminuria progression have not extensively investigated in clinical studies. We aimed to identify the relationship between total CO2 levels and albuminuria progression in a multicenter prospective cohort.

Methods

A total of 503 patients with at least two urinary albumin-to-creatinine ratios (UACR) measurements 1 year apart and no change in the dose of ACEi/ARB were enrolled. Participants were divided into the quartiles based on the time-averaged total CO2 levels during the 1-year follow-up; Q1(<24.7 mmol/L), Q2 (24.7-26.6 mmol/L), Q3 (26.7-28.5 mmol/L), and Q4(>28.6 mmol/L). We examined the albuminuria progression which is defined as A1 (<30 mg/g Cr) to A2 (30-300 mg/g Cr), A2 to A3 (>300mg/g Cr), and A1 to A3 according to the quartiles of total CO2.

Results

At baseline, 159 patients had A1 albuminuria, and 344 patients had A2 albuminuria. After 1 year follow-up, 96 patients revealed albuminuria progression; 26 from A1 to A2, 62 from A2 to A3, and 4 from A1 to A3. The percentage of subjects with albuminuria progression was higher in upper quartiles (P for trends <0.001). In multivariable logistic regression, the highest quartile of total CO2 was also significantly less likely associated with albuminuria progression compared with the lowest quartile (adjusted OR 0.31; 95% CI 0.13-0.77). In addition, multivariable linear regression using total CO2 as a continuous variable and UACR fold change also showed significant negative associations (β=-0.22, P=0.009).

Conclusion

In patients with CKD, total CO2 levels were independently associated with albuminuria progression over the 1-year interval. These results may suggest that high total CO2 levels could have beneficial effects on proteinuria progression in CKD patients even within the normal range of total CO2 levels.