TY - JOUR
T1 - Serum Bicarbonate Levels and the Progression of Kidney Disease
T2 - A Cohort Study
AU - Shah, Samir N.
AU - Abramowitz, Matthew
AU - Hostetter, Thomas H.
AU - Melamed, Michal L.
N1 - Funding Information:
Support: Dr Melamed is supported by Grant K23 DK078774 from the National Institute of Diabetes, Digestive and Kidney Diseases (NIDDK) of the National Institutes of Health (NIH). Dr Hostetter is supported by Grants R21 DK 077326 and RO1 DK080123 from the NIDDK of the NIH. Dr Abramowitz is supported by Grant T32 DK 007110-33 from the NIDDK of the NIH.
PY - 2009/8
Y1 - 2009/8
N2 - Background: Animal models of kidney disease have linked metabolic acidosis with renal damage. The role of low serum bicarbonate levels in kidney disease progression in humans has not been studied. Study Design: Retrospective cohort study. Setting & Participants: Adults visiting a medical clinic in the Bronx, NY, from January 1, 2001, to December 31, 2003, were included in the study (n = 5,422) and followed up until June 30, 2007. Predictor: Serum bicarbonate level. Outcomes: Kidney disease progression was defined as either a decrease in estimated glomerular filtration rate (eGFR) by 50% or reaching an eGFR less than 15 mL/min/1.73 m2 (n = 337). Measurements: Patients' baseline demographics, comorbid conditions, laboratory data, and socioeconomic status were recorded. Serial outpatient serum creatinine levels were collected (median, 5 measurements/person). Results: Mean age was 52 years, 69% were women, 45% were African American, 31% were Hispanic, 21% had diabetes mellitus, 41% had hypertension, and 9% had a baseline eGFR less than 60 mL/min/1.73 m2. Kidney disease progressed as defined in 337 patients (6.2%). Compared with the reference group (bicarbonate level, 25 to 26 mEq/L), hazard ratios for progression after adjustment for potential confounders were 1.54 (95% confidence interval [CI], 1.13 to 2.09) for bicarbonate levels of 22 mEq/L or less, 0.97 (95% CI, 0.70 to 1.35) for 23 to 24 mEq/L, and 1.14 (95% CI, 0.84 to 1.55) for 27 mEq/L or greater (global P for inclusion of serum bicarbonate level in the model = 0.01). These results were similar using different definitions of the outcome (eGFR decrease of 30%, 1,288 outcomes [24%]; or doubling of serum creatinine level, 268 outcomes [4.9%]). Limitations: Data used in the study were collected for clinical, not research, purposes. Conclusions: Low serum bicarbonate level is associated with progression of kidney disease independent of baseline eGFR and other clinical, demographic, and socioeconomic factors. Prospective studies are needed to confirm this relationship and evaluate the efficacy of alkali supplements for slowing progression.
AB - Background: Animal models of kidney disease have linked metabolic acidosis with renal damage. The role of low serum bicarbonate levels in kidney disease progression in humans has not been studied. Study Design: Retrospective cohort study. Setting & Participants: Adults visiting a medical clinic in the Bronx, NY, from January 1, 2001, to December 31, 2003, were included in the study (n = 5,422) and followed up until June 30, 2007. Predictor: Serum bicarbonate level. Outcomes: Kidney disease progression was defined as either a decrease in estimated glomerular filtration rate (eGFR) by 50% or reaching an eGFR less than 15 mL/min/1.73 m2 (n = 337). Measurements: Patients' baseline demographics, comorbid conditions, laboratory data, and socioeconomic status were recorded. Serial outpatient serum creatinine levels were collected (median, 5 measurements/person). Results: Mean age was 52 years, 69% were women, 45% were African American, 31% were Hispanic, 21% had diabetes mellitus, 41% had hypertension, and 9% had a baseline eGFR less than 60 mL/min/1.73 m2. Kidney disease progressed as defined in 337 patients (6.2%). Compared with the reference group (bicarbonate level, 25 to 26 mEq/L), hazard ratios for progression after adjustment for potential confounders were 1.54 (95% confidence interval [CI], 1.13 to 2.09) for bicarbonate levels of 22 mEq/L or less, 0.97 (95% CI, 0.70 to 1.35) for 23 to 24 mEq/L, and 1.14 (95% CI, 0.84 to 1.55) for 27 mEq/L or greater (global P for inclusion of serum bicarbonate level in the model = 0.01). These results were similar using different definitions of the outcome (eGFR decrease of 30%, 1,288 outcomes [24%]; or doubling of serum creatinine level, 268 outcomes [4.9%]). Limitations: Data used in the study were collected for clinical, not research, purposes. Conclusions: Low serum bicarbonate level is associated with progression of kidney disease independent of baseline eGFR and other clinical, demographic, and socioeconomic factors. Prospective studies are needed to confirm this relationship and evaluate the efficacy of alkali supplements for slowing progression.
KW - Serum bicarbonate
KW - kidney disease progression
KW - metabolic acidosis
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U2 - 10.1053/j.ajkd.2009.02.014
DO - 10.1053/j.ajkd.2009.02.014
M3 - Article
C2 - 19394734
AN - SCOPUS:67650424024
SN - 0272-6386
VL - 54
SP - 270
EP - 277
JO - American Journal of Kidney Diseases
JF - American Journal of Kidney Diseases
IS - 2
ER -
