Serum bicarbonate and mortality in adults in NHANES III

Kalani L. Raphael, Yingying Zhang, Guo Wei, Tom Greene, Alfred K. Cheung, Srinivasan Beddhu

Research output: Contribution to journalArticlepeer-review

74 Scopus citations


Background Low serum bicarbonate concentration is a risk factor for death in people with chronic kidney disease (CKD). Whether low serum bicarbonate is a mortality risk factor for people without CKD is unknown. Methods National Health and Nutrition Examination Survey III (NHANES III) adult participants were categorized into one of four serum bicarbonate categories: <22, 22-25, 26-30 and ≥31 mM. Cox models were used to determine the hazards of death in each serum bicarbonate category, using 26-30 mM as the reference group, in the (i) entire population, (ii) non-CKD subgroup and (iii) CKD subgroup.ResultsAfter adjusting for age, gender, race, estimated glomerular filtration rate, albuminuria, diuretic use, smoking, C-reactive protein, cardiovascular disease, protein intake, diabetes, hypertension, body mass index, lung disease and serum albumin, the hazards of death in the <22 mM serum bicarbonate category were 1.75 (95% CI: 1.12-2.74), 1.56 (95% CI: 0.78-3.09) and 2.56 (95% CI: 1.49-4.38) in the entire population, non-CKD subgroup and CKD subgroup, respectively, compared with the reference group. Hazard ratios in the other serum bicarbonate categories in the entire population and non-CKD and CKD subgroups did not differ from the reference group. Conclusions Among the NHANES III participants, low serum bicarbonate was not observed to be a strong predictor of mortality in people without CKD. However, low serum bicarbonate was associated with a 2.6-fold increased hazard of death in people with CKD.

Original languageEnglish (US)
Pages (from-to)1207-1213
Number of pages7
JournalNephrology Dialysis Transplantation
Issue number5
StatePublished - May 2013
Externally publishedYes


  • bicarbonate
  • chronic kidney disease
  • mortality

ASJC Scopus subject areas

  • Nephrology
  • Transplantation


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