Serum bicarbonate and mortality in adults in NHANES III.
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.


RESULTS
After 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.
Salt Lake City VA Healthcare System, Salt Lake City, UT, USA. kalani.raphael@hsc.utah.edu
Kalani L
KL
Raphael
Yingying
Y
Zhang
Guo
G
Wei
Tom
T
Greene
Alfred K
AK
Cheung
Srinivasan
S
Beddhu
D000328:Adult; D000368:Aged; D000419:Albuminuria / Q000097:blood / Q000401:mortality*; D001639:Bicarbonates / Q000097:blood*; D015415:Biomarkers / Q000097:blood*; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000097:blood / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D011379:Prognosis; D051436:Renal Insufficiency, Chronic / Q000097:blood / Q000401:mortality*; D012307:Risk Factors; D015996:Survival Rate
D001639:Bicarbonates; D015415:Biomarkers
bicarbonate; chronic kidney disease; mortality