title: Prevalence of and risk factors for reduced serum bicarbonate in chronic kidney disease.
abstract: OBJECTIVE
  The prevalence of metabolic acidosis increases as glomerular filtration rate falls. However, most patients with stage 4 chronic kidney disease have normal serum bicarbonate concentration while some with stage 3 chronic kidney disease have low serum bicarbonate, suggesting that other factors contribute to generation of acidosis. The purpose of this study is to identify risk factors, other than reduced glomerular filtration rate, for reduced serum bicarbonate in chronic kidney disease.
  
  
  METHODS
  This is a cross-sectional analysis of baseline data from the Chronic Renal Insufficiency Cohort Study. Multivariable logistic and linear regression models were used to relate predictor variables to the odds of low serum bicarbonate (< 22 mM) compared with normal serum bicarbonate (22-30 mM) and the coefficients of Δ serum bicarbonate concentration.
  
  
  RESULTS
  The prevalence of low serum bicarbonate at baseline was 17.3%. Lower estimated glomerular filtration rate had the strongest relationship with low serum bicarbonate. Factors associated with higher odds of low serum bicarbonate, independent of estimated glomerular filtration rate, were urinary albumin/creatinine ≥ 10 mg/g, smoking, anaemia, hyperkalaemia, non-diuretic use and higher serum albumin. These and younger age, higher waist circumference, and use of angiotensin converting enzyme inhibitors or angiotensin receptor blockers associated with negative Δ serum bicarbonate in linear regression models.
  
  
  CONCLUSIONS
  Several factors not typically considered to associate with reduced serum bicarbonate in chronic kidney disease were identified including albuminuria ≥ 10 mg/g, anaemia, smoking, higher serum albumin, higher waist circumference, and use of angiotensin converting enzyme inhibitors or angiotensin receptor blockers. Future studies should explore the longitudinal effect of these factors on serum bicarbonate concentration.
authors: Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA; Salt Lake City VA Health Care System, Salt Lake City, UT, USA.
authors: Kalani L
authors: KL
authors: Raphael
authors: Yingying
authors: Y
authors: Zhang
authors: Jian
authors: J
authors: Ying
authors: Tom
authors: T
authors: Greene
mesh_terms: D000138:Acidosis / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology*; D000328:Adult; D000368:Aged; D001639:Bicarbonates / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D018450:Disease Progression; D015536:Down-Regulation; D005260:Female; D006801:Humans; D016014:Linear Models; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D015995:Prevalence; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology*; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult
chemical_list: D001639:Bicarbonates; D015415:Biomarkers
keywords: albuminuria; chronic kidney disease; glomerular filtration rate; metabolic acidosis; smoking