title: Adjusted Anion Gap Is Associated with Glomerular Filtration Rate Decline in Chronic Kidney Disease.
abstract: BACKGROUND
  Metabolic acidosis is known to accelerate the progression of chronic kidney disease (CKD). However, whether undetermined anions as indicated by the adjusted anion gap (aAG) are associated with estimated glomerular filtration rate (eGFR) decline in patients with CKD is unclear.
  
  
  METHODS
  Data from 42 patients with CKD (baseline eGFR, 7.1-52.0 ml/min/ 1.73 m2) without massive proteinuria (urinary protein-creatinine ratio, UPCR <3.5) were retrospectively analyzed. aAG was calculated from serum sodium, serum chloride, serum bicarbonate, serum albumin, serum potassium, serum calcium and serum phosphate. The association between the percentage of the 6-month change of eGFR (%ΔeGFR/6m) and aAG was examined.
  
  
  RESULTS
  The mean baseline eGFR was 27.5 ± 11.1 ml/min/1.73 m2and the mean %ΔeGFR/6m was 13.8 ± 10.3. UPCR and aAG were 1.13 ± 0.93 and 9.48 ± 1.88, respectively. %ΔeGFR/6m was associated with aAG (r = 0.438, p < 0.005), but not with UPCR (r = 0.194, p = 0.218). In multivariate linear regression analyses, aAG remained significantly associated with %ΔeGFR/6m (β = 0.45, p < 0.01) after controlling for age, baseline eGFR, UPCR and HCO3-concentration.
  
  
  CONCLUSIONS
  These data suggest that aAG appears to be associated with the progression of CKD. aAG might be an independent predictor of CKD progression.
authors.affiliation: Department of Nephrology, Shizuoka Saiseikai General Hospital, Tokyo, Japan.
authors.forename: Akashi
authors.initials: A
authors.lastname: Togawa
authors.affiliation: Department of Nephrology, Shizuoka Saiseikai General Hospital, Tokyo, Japan.
authors.forename: Satoko
authors.initials: S
authors.lastname: Uyama
authors.affiliation: Department of Nephrology, Shizuoka Saiseikai General Hospital, Tokyo, Japan.
authors.forename: Seiko
authors.initials: S
authors.lastname: Takanohashi
authors.affiliation: Department of Nephrology, Shizuoka Saiseikai General Hospital, Tokyo, Japan.
authors.forename: Megumi
authors.initials: M
authors.lastname: Shimasaki
authors.affiliation: Miyaji Clinic, Hamamatsu University School of Medicine, Hamamatsu, Tokyo, Japan.
authors.forename: Takehiko
authors.initials: T
authors.lastname: Miyaji
authors.affiliation: Tanpopo Clinic, Shizuoka, Hamamatsu University School of Medicine, Hamamatsu, Tokyo, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Endo
authors.affiliation: Internal Medicine 1, Hamamatsu University School of Medicine, Hamamatsu, Tokyo, Japan ; Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan.
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Fujigaki
keywords: Adjusted anion gap; Chronic kidney disease; Glomerular filtration rate decline