Association of serum bicarbonate with risk of renal and cardiovascular outcomes in CKD: A report from the Chronic Renal Insufficiency Cohort (CRIC) study

Mirela Dobre, Wei Yang, Jing Chen, Paul Drawz, L. Lee Hamm, Edward Horwitz, Thomas Hostetter, Bernard Jaar, Claudia M. Lora, Lisa Nessel, Akinlolu Ojo, Julia Scialla, Susan Steigerwalt, Valerie Teal, Myles Wolf, Mahboob Rahman

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104 Scopus citations

Abstract

Background: The purpose of this study is to evaluate serum bicarbonate level as a risk factor for renal outcomes, cardiovascular events, and mortality in patients with chronic kidney disease (CKD). Study Design: Observational cohort study. Setting & Participants: 3,939 participants with CKD stages 2-4 who enrolled in the Chronic Renal Insufficiency Cohort (CRIC) between June 2003 and December 2008. Predictor: Serum bicarbonate level. Outcomes: Renal outcomes, defined as end-stage renal disease (either initiation of dialysis therapy or kidney transplantation) or 50% reduction in estimated glomerular filtration rate (eGFR); atherosclerotic events (myocardial infarction, stroke, or peripheral arterial disease); congestive heart failure events; and death. Measurements: Time to event. Results: Mean eGFR was 44.8 ± 16.8 (SD) mL/min/1.73 m2, and median serum bicarbonate level was 24 (IQR, 22-26) mEq/L. During a median follow-up of 3.9 years, 374 participants died, 767 had a renal outcome, 332 experienced an atherosclerotic event, and 391 had a congestive heart failure event. In adjusted analyses, the risk of developing a renal end point was 3% lower per 1-mEq/L increase in serum bicarbonate level (HR, 0.97; 95% CI, 0.94-0.99; P = 0.01). The association was stronger for participants with eGFR >45 mL/min/1.73 m2 (HR, 0.91; 95% CI, 0.85-0.97; P = 0.004). The risk of heart failure increased by 14% (HR, 1.14; 95% CI, 1.03-1.26; P = 0.02) per 1-mEq/L increase in serum bicarbonate level over 24 mEq/L. Serum bicarbonate level was not associated independently with atherosclerotic events (HR, 0.99; 95% CI, 0.95-1.03; P = 0.6) and all-cause mortality (HR, 0.98; 95% CI, 0.95-1.02; P = 0.3). Limitations: Single measurement of sodium bicarbonate. Conclusions: In a cohort of participants with CKD, low serum bicarbonate level was an independent risk factor for kidney disease progression, particularly for participants with preserved kidney function. The risk of heart failure was higher at the upper extreme of serum bicarbonate levels. There was no association between serum bicarbonate level and all-cause mortality or atherosclerotic events.

Original languageEnglish (US)
Pages (from-to)670-678
Number of pages9
JournalAmerican Journal of Kidney Diseases
Volume62
Issue number4
DOIs
StatePublished - Oct 2013

Keywords

  • cardiovascular morbidity
  • chronic kidney disease
  • Metabolic acidosis
  • serum bicarbonate

ASJC Scopus subject areas

  • Nephrology

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    Dobre, M., Yang, W., Chen, J., Drawz, P., Hamm, L. L., Horwitz, E., Hostetter, T., Jaar, B., Lora, C. M., Nessel, L., Ojo, A., Scialla, J., Steigerwalt, S., Teal, V., Wolf, M., & Rahman, M. (2013). Association of serum bicarbonate with risk of renal and cardiovascular outcomes in CKD: A report from the Chronic Renal Insufficiency Cohort (CRIC) study. American Journal of Kidney Diseases, 62(4), 670-678. https://doi.org/10.1053/j.ajkd.2013.01.017