title: Low serum bicarbonate and kidney function decline: the Multi-Ethnic Study of Atherosclerosis (MESA).
abstract: BACKGROUND
  Among populations with established chronic kidney disease (CKD), metabolic acidosis is associated with more rapid progression of kidney disease. The association of serum bicarbonate concentrations with early declines in kidney function is less clear.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  5,810 participants in the Multi-Ethnic Study of Atherosclerosis (MESA) with a baseline estimated glomerular filtration rate (eGFR) > 60mL/min/1.73 m(2) using the CKD-EPI (CKD Epidemiology Collaboration) creatinine-cystatin C equation.
  
  
  METHODS
  Serum bicarbonate concentrations.
  
  
  RESULTS
  Rapid kidney function decline (eGFR decline > 5% per year) and incident reduced eGFR (eGFR < 60mL/min/1.73 m(2) with minimum rate of eGFR loss of 1 mL/min/1.73 m(2) per year).
  
  
  RESULTS
  Average bicarbonate concentration was 23.2 ± 1.8mEq/L. 1,730 (33%) participants had rapid kidney function decline, and 487 had incident reduced eGFR during follow-up. Each 1-SD lower baseline bicarbonate concentration was associated with 12% higher adjusted odds of rapid kidney function decline (95% CI, 6%-20%) and higher risk of incident reduced eGFR (adjusted incidence rate ratio, 1.11; 95% CI, 1.03-1.20) in models adjusting for demographics, baseline eGFR, albuminuria, and CKD risk factors. The OR for the associations of bicarbonate level < 21 mEq/L relative to 23-24 mEq/L was 1.35 (95% CI, 1.05-1.73) for rapid kidney function decline, and the incidence rate ratio was 1.16 (95% CI, 0.83-1.62) for incident reduced eGFR.
  
  
  CONCLUSIONS
  Cause of metabolic acidosis cannot be determined in this study.
  
  
  CONCLUSIONS
  Lower serum bicarbonate concentrations are associated independently with rapid kidney function decline independent of eGFR or albuminuria in community-living persons with baseline eGFR > 60 mL/min/1.73 m(2). If confirmed, our findings suggest that metabolic acidosis may indicate either early kidney disease that is not captured by eGFR or albuminuria or may have a causal role in the development of eGFR < 60 mL/min/1.73 m(2).
authors: School of Medicine, University of California, San Francisco.
authors: Todd H
authors: TH
authors: Driver
authors: Department of Medicine, University of California, San Francisco; Department of Epidemiology and Biostatistics, University of California, San Francisco; Department of General Internal Medicine, San Francisco VA Medical Center, San Francisco, CA.
authors: Michael G
authors: MG
authors: Shlipak
authors: Kidney Research Institute, Division of Nephrology, University of Washington, Seattle, WA.
authors: Ronit
authors: R
authors: Katz
authors: Division of Nephrology and Hypertension, Department of Medicine, University of California, San Diego, CA.
authors: Leonard
authors: L
authors: Goldenstein
authors: Division of Nephrology, Tufts Medical Center, Boston, MA.
authors: Mark J
authors: MJ
authors: Sarnak
authors: Kidney Research Institute, Division of Nephrology, University of Washington, Seattle, WA.
authors: Andrew N
authors: AN
authors: Hoofnagle
authors: Kidney Research Institute, Division of Nephrology, University of Washington, Seattle, WA; Cardiovascular Health Research Unit, University of Washington, Seattle, WA; Department of Medicine, University of Washington, Seattle, WA; Department of Epidemiology, University of Washington, Seattle, WA.
authors: David S
authors: DS
authors: Siscovick
authors: Kidney Research Institute, Division of Nephrology, University of Washington, Seattle, WA.
authors: Bryan
authors: B
authors: Kestenbaum
authors: Kidney Research Institute, Division of Nephrology, University of Washington, Seattle, WA.
authors: Ian H
authors: IH
authors: de Boer
authors: Division of Nephrology and Hypertension, Department of Medicine, University of California, San Diego, CA; Division of Preventive Medicine, Department of Family and Preventive Medicine, University of California, San Diego, CA; Nephrology Section, Veterans Affairs San Diego Healthcare System, San Diego, CA. Electronic address: joeix@ucsd.edu.
authors: Joachim H
authors: JH
authors: Ix
mesh_terms: D000138:Acidosis / Q000097:blood*; D000368:Aged; D000419:Albuminuria / Q000453:epidemiology / Q000378:metabolism; D050197:Atherosclerosis / Q000378:metabolism; D001639:Bicarbonates / Q000097:blood*; D015331:Cohort Studies; D003404:Creatinine / Q000032:analysis; D055316:Cystatin C / Q000032:analysis; D018450:Disease Progression; D005006:Ethnicity; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007677:Kidney Function Tests / Q000379:methods; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis / Q000208:ethnology / Q000378:metabolism / Q000503:physiopathology; D012307:Risk Factors; D013223:Statistics as Topic; D014481:United States / Q000453:epidemiology
chemical_list: D001639:Bicarbonates; D055316:Cystatin C; D003404:Creatinine
keywords: Serum bicarbonate; chronic kidney disease (CKD); disease progression; kidney disease trajectory; kidney function; metabolic acidosis; renal disease