Kidney Week

Abstract: FR-PO429

Association of Low Bicarbonate with Increased Risk of Mortality, Dialysis, and Hospitalization in CKD Patients

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

• Buysse, Jerry M., Tricida, Inc, South San Francisco, California, United States

Jerry M. Buysse,

• Bushinsky, David A., University of Rochester Medical Center, Rochester, New York, United States

David A. Bushinsky,

• Li, Elizabeth, PharmaStat, LLC, Newark, California, United States

Elizabeth Li,

• McNulty, Sarah, Tricida, Inc., South San Francisco, California, United States

Sarah McNulty,

• Klaerner, Gerrit, Tricida, Inc., South San Francisco, California, United States

Gerrit Klaerner,

Background

Low bicarbonate has been associated with a higher risk of mortality, dialysis, and hospitalizations in CKD patients. Here we estimate these risks across different levels of low bicarbonate, compared to normal, in a database of 59,710 patients with stage 3-5 CKD (ICD9 585.4, 585.5) or eGFR <60 mL/min/1.73m² (Optum Electronic Health Record Dataset, 2007 – 2016).

Methods

Within this database, 43,777 patients were identified with a baseline bicarbonate of >12 to <29 mEq/L and baseline eGFR <60 mL/min/1.73m². Time-to-event analyses on this dataset evaluated death, progression to dialysis, and first hospitalization or emergency room (ER) visit by baseline bicarbonate groups: 12 – 20 (low), >20 – 22 (moderately low), and >22 – <29 (normal) mEq/L. Hazard ratios (HRs; 95% CIs) for these outcomes in the low and moderately low groups, compared with normal, were determined using a Cox regression model adjusted for time-independent covariates (age, gender, diabetes, hypertension, cerebrovascular disease, and baseline eGFR).

Results

Bicarbonate was low in 6,558 (15%), moderately low in 6,599 (15%) and normal in 30,620 (70%) of patients and the overall mean eGFR was 34.9 mL/min/1.73m². Compared with normal, the mortality HRs were 2.63 (95% CI, 2.46 to 2.80) in the low and 1.47 (95% CI, 1.36 to 1.59) in the moderately low bicarbonate groups (p<0.0001). The HRs for progression to dialysis and hospitalization/ER visits were 1.46 (95% CI, 1.32 to 1.62) and 1.46 (95% CI, 1.38 to 1.55), respectively, in the low bicarbonate group (p<0.0001); in contrast, the moderately low bicarbonate group had the same risk as normal for these outcomes [1.10 (95% CI 0.97, 1.24), p=0.13 and 1.08 (95% CI 1.01, 1.15), p=0.02, respectively, for dialysis and hospitalization/ER visits].

Conclusion

There is a strong correlation between low bicarbonate and risk of adverse outcomes (death, dialysis, hospitalizations or ER visits) in CKD, and the risk of these outcomes is significantly greater in patients with low bicarbonate levels (12 – 20 mEq/L) compared to those with normal bicarbonate levels (>22 – <29 mEq/L).

Funding

• Commercial Support – Tricida, Inc.