title: Association between lower serum bicarbonate and renal hyperfiltration in the general population with preserved renal function: a cross-sectional study.
abstract: BACKGROUND
  Lower serum bicarbonate, mainly due to the modern Western-style diet, and renal hyperfiltration (RHF) are both independently associated with higher mortality in the general population with preserved renal function. The objective of this study was to evaluate the association between serum bicarbonate and RHF.
  
  
  METHODS
  The health data of 41,886 adults with an estimated glomerular filtration rate (eGFR) ≥60 mL/min per 1.73 m(2) were analyzed. The eGFR was calculated with the Chronic Kidney Disease Epidemiology Collaboration creatinine equation and RHF was defined as eGFR with adjusted residuals > sex-specific 95(th) percentile.
  
  
  RESULTS
  The adjusted mean of eGFR was lower in the highest quintile of serum bicarbonate than in other quintiles, after adjusting for confounders. A lower percentile rank of serum bicarbonate was associated with higher odds of RHF. The odds ratio (OR) for RHF in the lowest quintile of serum bicarbonate was 1.39 (95 % confidence interval, 95 % CI, 1.11-1.75) compared to the highest, after adjusting for confounders. With subgroup analysis, the association was prominent in participants with a body mass index >25 kg/m(2) (OR 1.98, 95 % CI 1.32-2.95 in the lowest quintile compared to the highest), compared to those with a body mass index ≤25 kg/m(2) (OR 1.18, 95 % CI 0.89-1.56 in the lowest quintile compared to the highest).
  
  
  CONCLUSIONS
  This study observed an association between lower serum bicarbonate and higher odds of RHF and the possible differential effect of obesity in this association. It is necessary to confirm the association between lower serum bicarbonate and RHF and its causality.
authors.affiliation: Department of Family Medicine, Seoul National University Hospital, Seoul, Republic of Korea.
authors.forename: Minseon
authors.initials: M
authors.lastname: Park
authors.affiliation: Department of Biomedical Engineering, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, Republic of Korea.
authors.forename: Rina
authors.initials: R
authors.lastname: So
authors.affiliation: Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
authors.forename: Kwon Wook
authors.initials: KW
authors.lastname: Joo
authors.affiliation: Department of Biomedical Engineering, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, Republic of Korea. hjyoon@snu.ac.kr.
authors.forename: Hyung-Jin
authors.initials: HJ
authors.lastname: Yoon
mesh_terms: D001639:Bicarbonates / Q000097:blood*; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology; D016017:Odds Ratio
chemical_list: D001639:Bicarbonates