Kidney Week

Abstract: FR-PO430

The Association of Metabolic Acidosis with Renal Progression in CKD: Results from the KNOW-CKD Study

Session Information

• CKD: Risk Factors for Incidence and Progression - II
  November 03, 2017 | Location: Hall H, Morial Convention Center
  Abstract Time: 10:00 AM - 10:00 AM

Category: Chronic Kidney Disease (Non-Dialysis)

• 301 CKD: Risk Factors for Incidence and Progression

Authors

• Kim, Hyo Jin, Dongguk University College of Medicine, Gyeongju-si, Korea (the Republic of)

Hyo Jin Kim,

• Ryu, Hyunjin, Seoul National University Bundang Hospital, Seongnam, GyeongGi-Do, Korea (the Republic of)

Hyunjin Ryu,

• Kang, Eunjeong, Seoul National University Bundang Hospital, Seongnam, GyeongGi-Do, Korea (the Republic of)

Eunjeong Kang,

• Han, Miyeun, Seoul National University College of Medicine, Seoul, Korea (the Republic of)

Miyeun Han,

• Ahn, Curie, Seoul National University Bundang Hospital, Seongnam, GyeongGi-Do, Korea (the Republic of)

Curie Ahn,

• Oh, Kook-Hwan, Seoul National University Bundang Hospital, Seongnam, GyeongGi-Do, Korea (the Republic of)

Kook-Hwan Oh,

Background

Metabolic acidosis, usually manifested by low serum bicarbonate level, is prevalent in chronic kidney disease (CKD). However, its relationship to long-term outcomes is unclear in Korean CKD patients. The purpose of the present study is to evaluate serum bicarbonate as a risk factor for renal outcomes, cardiovascular events and mortality in large-scale Korean CKD cohort patients.

Methods

Among the subjects recruited in the KoreaN Cohort Study for Outcome in Patients With Chronic Kidney Disease (KNOW-CKD) between 2011 and 2016, we analyzed 1,809 participants who measured for serum bicarbonate levels. Serum bicarbonate level was categorized as low, lower normal, higher normal, and high (< 22, 22-26, 26.1-29.1, ≥30 mmol/L, respectively) groups. Metabolic acidosis was defined as serum bicarbonate < 22 mmol/L. The primary outcome was renal events defined as doubling of serum creatinine, 50% reduction in eGFR from the baseline values, or end-stage renal disease. The secondary composite outcome consisted of cardiovascular events and death.

Results

Patients were 53.6±12.3 years old. The mean serum bicarbonate level was 25.7±3.7 mmol/L. A total 240 (13.3%) patients had metabolic acidosis. Patients were followed for 36.3±17.5 months. After adjustment, there was no significant association between serum bicarbonate and renal outcomes. There was significant interaction of serum bicarbonate with eGFR (interaction P=0.029). In an analysis with adjustment, in a subgroup with eGFR ≤45ml/min/1.73m², the risk of developing renal outcomes was significantly increased with decreasing (HR, 0.91; 95% CI, 0.87-0.94; P<0.001) and the low bicarbonate group was associated with a HR of 1.72 (95% CI, 1.28-2.32; P<0.001) compared with lower normal group. Serum bicarbonate was not independently associated with renal outcomes in those with eGFR >45ml/min/1.73m² (HR 0.92; 95% CI, 0.78-1.08; P=0.297). Serum bicarbonate was not independently associated with secondary outcomes neither in eGFR ≤45 (HR 0.96; 95% CI, 0.89-1.04; P=0.339) nor in eGFR >45ml/min/1.73m² (HR 0.90; 95% CI, 0.79-1.02; P=0.086).

Conclusion

In a cohort of participants with CKD, metabolic acidosis was an independent risk factor for renal progression, particularly for those with advanced decreasing kidney function.

Funding

• Government Support - Non-U.S.