title: Association of serum bicarbonate with risk of renal and cardiovascular outcomes in CKD: a report from the Chronic Renal Insufficiency Cohort (CRIC) study.
abstract: BACKGROUND
  The purpose of this study is to evaluate serum bicarbonate level as a risk factor for renal outcomes, cardiovascular events, and mortality in patients with chronic kidney disease (CKD).
  
  
  METHODS
  Observational cohort study.
  
  
  METHODS
  3,939 participants with CKD stages 2-4 who enrolled in the Chronic Renal Insufficiency Cohort (CRIC) between June 2003 and December 2008.
  
  
  METHODS
  Serum bicarbonate level.
  
  
  RESULTS
  Renal outcomes, defined as end-stage renal disease (either initiation of dialysis therapy or kidney transplantation) or 50% reduction in estimated glomerular filtration rate (eGFR); atherosclerotic events (myocardial infarction, stroke, or peripheral arterial disease); congestive heart failure events; and death.
  
  
  METHODS
  Time to event.
  
  
  RESULTS
  Mean eGFR was 44.8 ± 16.8 (SD) mL/min/1.73 m(2), and median serum bicarbonate level was 24 (IQR, 22-26) mEq/L. During a median follow-up of 3.9 years, 374 participants died, 767 had a renal outcome, 332 experienced an atherosclerotic event, and 391 had a congestive heart failure event. In adjusted analyses, the risk of developing a renal end point was 3% lower per 1-mEq/L increase in serum bicarbonate level (HR, 0.97; 95% CI, 0.94-0.99; P = 0.01). The association was stronger for participants with eGFR >45 mL/min/1.73 m(2) (HR, 0.91; 95% CI, 0.85-0.97; P = 0.004). The risk of heart failure increased by 14% (HR, 1.14; 95% CI, 1.03-1.26; P = 0.02) per 1-mEq/L increase in serum bicarbonate level over 24 mEq/L. Serum bicarbonate level was not associated independently with atherosclerotic events (HR, 0.99; 95% CI, 0.95-1.03; P = 0.6) and all-cause mortality (HR, 0.98; 95% CI, 0.95-1.02; P = 0.3).
  
  
  CONCLUSIONS
  Single measurement of sodium bicarbonate.
  
  
  CONCLUSIONS
  In a cohort of participants with CKD, low serum bicarbonate level was an independent risk factor for kidney disease progression, particularly for participants with preserved kidney function. The risk of heart failure was higher at the upper extreme of serum bicarbonate levels. There was no association between serum bicarbonate level and all-cause mortality or atherosclerotic events.
authors.affiliation: Case Western Reserve University, Cleveland, OH; Division of Nephrology and Hypertension, University Hospital Case Medical Center, Cleveland, OH; Louis Stokes Cleveland VA Medical Center, Cleveland, OH. Electronic address: mirela.dobre@uhhospitals.org.
authors.forename: Mirela
authors.initials: M
authors.lastname: Dobre
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.forename: Paul
authors.initials: P
authors.lastname: Drawz
authors.forename: L Lee
authors.initials: LL
authors.lastname: Hamm
authors.forename: Edward
authors.initials: E
authors.lastname: Horwitz
authors.forename: Thomas
authors.initials: T
authors.lastname: Hostetter
authors.forename: Bernard
authors.initials: B
authors.lastname: Jaar
authors.forename: Claudia M
authors.initials: CM
authors.lastname: Lora
authors.forename: Lisa
authors.initials: L
authors.lastname: Nessel
authors.forename: Akinlolu
authors.initials: A
authors.lastname: Ojo
authors.forename: Julia
authors.initials: J
authors.lastname: Scialla
authors.forename: Susan
authors.initials: S
authors.lastname: Steigerwalt
authors.forename: Valerie
authors.initials: V
authors.lastname: Teal
authors.forename: Myles
authors.initials: M
authors.lastname: Wolf
authors.forename: Mahboob
authors.initials: M
authors.lastname: Rahman
mesh_terms: D000328:Adult; D000368:Aged; D001639:Bicarbonates / Q000097:blood*; D002318:Cardiovascular Diseases / Q000097:blood* / Q000453:epidemiology* / Q000209:etiology / Q000401:mortality; D015331:Cohort Studies; D018450:Disease Progression; D005260:Female; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood / Q000453:epidemiology / Q000209:etiology / Q000401:mortality; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000150:complications*; D012307:Risk Factors; D055815:Young Adult
chemical_list: D001639:Bicarbonates
keywords: Metabolic acidosis; cardiovascular morbidity; chronic kidney disease; serum bicarbonate