TY - JOUR
T1 - Bicarbonate concentration, acid-base status, and mortality in the health, aging, and body composition study
AU - Raphael, Kalani L.
AU - Murphy, Rachel A.
AU - Shlipak, Michael G.
AU - Satterfield, Suzanne
AU - Huston, Hunter K.
AU - Sebastian, Anthony
AU - Sellmeyer, Deborah E.
AU - Patel, Kushang V.
AU - Newman, Anne B.
AU - Sarnak, Mark J.
AU - Ix, Joachim H.
AU - Fried, Linda F.
N1 - Publisher Copyright:
© 2016 by the American Society of Nephrology
PY - 2016/2/5
Y1 - 2016/2/5
N2 - Background and objectives Low serum bicarbonate associates with mortality in CKD. This study investigated the associations of bicarbonate and acid-base status with mortality in healthy older individuals. Design, setting, participants, & measurements We analyzed data from the Health, Aging, and Body Composition Study, a prospective study of well functioning black and white adults ages 70–79 years old from 1997. Participants with arterialized venous blood gas measurements (n=2287) were grouped into <23.0 mEq/L (low), 23.0–27.9 mEq/L (reference group), and ≥28.0 mEq/L (high) bicarbonate categories and according to acid-base status. Survival data were collected through February of 2014. Mortality hazard ratios (HRs; 95% confidence intervals [95% CIs]) in the low and high bicarbonate groups compared with the reference group were determined using Cox models adjusted for demographics, eGFR, albuminuria, chronic obstructive pulmonary disease, smoking, and systemic pH. Similarly adjusted Cox models were performed according to acid-base status. Results The mean age was 76 years, 51% were women, and 38% were black. Mean pH was 7.41, mean bicarbonate was 25.1 mEq/L, 11% had low bicarbonate, and 10% had high bicarbonate. Mean eGFR was 82.1 ml/min per 1.73 m2, and 12% had CKD. Over a mean follow-up of 10.3 years, 1326 (58%) participants died. Compared with the reference group, the mortality HRs were 1.24 (95% CI, 1.02 to 1.49) in the low bicarbonate and 1.03 (95% CI, 0.84 to 1.26) in the high bicarbonate categories. Compared with the normal acid-base group, the mortality HRs were 1.17 (95% CI, 0.94 to 1.47) for metabolic acidosis, 1.21 (95% CI, 1.01 to 1.46) for respiratory alkalosis, and 1.35 (95% CI, 1.08 to 1.69) for metabolic alkalosis categories. Respiratory acidosis did not associate with mortality. Conclusions In generally healthy older individuals, low serum bicarbonate associated with higher mortality independent of systemic pH and potential confounders. This association seemed to be present regardless of whether the cause of low bicarbonate was metabolic acidosis or respiratory alkalosis. Metabolic alkalosis also associated with higher mortality.
AB - Background and objectives Low serum bicarbonate associates with mortality in CKD. This study investigated the associations of bicarbonate and acid-base status with mortality in healthy older individuals. Design, setting, participants, & measurements We analyzed data from the Health, Aging, and Body Composition Study, a prospective study of well functioning black and white adults ages 70–79 years old from 1997. Participants with arterialized venous blood gas measurements (n=2287) were grouped into <23.0 mEq/L (low), 23.0–27.9 mEq/L (reference group), and ≥28.0 mEq/L (high) bicarbonate categories and according to acid-base status. Survival data were collected through February of 2014. Mortality hazard ratios (HRs; 95% confidence intervals [95% CIs]) in the low and high bicarbonate groups compared with the reference group were determined using Cox models adjusted for demographics, eGFR, albuminuria, chronic obstructive pulmonary disease, smoking, and systemic pH. Similarly adjusted Cox models were performed according to acid-base status. Results The mean age was 76 years, 51% were women, and 38% were black. Mean pH was 7.41, mean bicarbonate was 25.1 mEq/L, 11% had low bicarbonate, and 10% had high bicarbonate. Mean eGFR was 82.1 ml/min per 1.73 m2, and 12% had CKD. Over a mean follow-up of 10.3 years, 1326 (58%) participants died. Compared with the reference group, the mortality HRs were 1.24 (95% CI, 1.02 to 1.49) in the low bicarbonate and 1.03 (95% CI, 0.84 to 1.26) in the high bicarbonate categories. Compared with the normal acid-base group, the mortality HRs were 1.17 (95% CI, 0.94 to 1.47) for metabolic acidosis, 1.21 (95% CI, 1.01 to 1.46) for respiratory alkalosis, and 1.35 (95% CI, 1.08 to 1.69) for metabolic alkalosis categories. Respiratory acidosis did not associate with mortality. Conclusions In generally healthy older individuals, low serum bicarbonate associated with higher mortality independent of systemic pH and potential confounders. This association seemed to be present regardless of whether the cause of low bicarbonate was metabolic acidosis or respiratory alkalosis. Metabolic alkalosis also associated with higher mortality.
KW - Acid-base equilibrium
KW - Acidosis
KW - Bicarbonate
KW - Body composition
KW - Follow-up studies
KW - Glomerular filtration rate
KW - Humans
KW - Mortality
KW - Prospective studies
KW - Renal insufficiency, chronic
UR - http://www.scopus.com/inward/record.url?scp=84957073008&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84957073008&partnerID=8YFLogxK
U2 - 10.2215/CJN.06200615
DO - 10.2215/CJN.06200615
M3 - Article
C2 - 26769766
AN - SCOPUS:84957073008
SN - 1555-9041
VL - 11
SP - 308
EP - 316
JO - Clinical Journal of the American Society of Nephrology
JF - Clinical Journal of the American Society of Nephrology
IS - 2
ER -