title: Predialysis and Postdialysis pH and Bicarbonate and Risk of All-Cause and Cardiovascular Mortality in Long-term Hemodialysis Patients.
abstract: BACKGROUND
  To date, very few studies have been carried out on the associations of pre- and postdialysis acid-base parameters with mortality in hemodialysis patients.
  
  
  METHODS
  An observational study including cross-sectional and 1-year analyses.
  
  
  METHODS
  Data from the renal registry of the Japanese Society of Dialysis Therapy (2008-2009), including 15,132 dialysis patients 16 years or older.
  
  
  METHODS
  Predialysis pH<7.30, 7.30 to 7.34 (reference), 7.35 to 7.39, or ≥7.40 (1,550, 4,802, 6,023, and 2,757 patients, respectively); predialysis bicarbonate level < 18.0, 18.0 to 21.9 (reference), 22.0 to 25.9, or ≥26.0 mEq/L (2,724, 7,851, 4,023, and 534 patients, respectively); postdialysis pH<7.40, 7.40 to 7.44, 7.45 to 7.49 (reference), or ≥7.50 (2,114, 5,331, 4,975, and 2,712 patients, respectively); and postdialysis bicarbonate level < 24.0, 24.0 to 25.9, 26.0 to 27.9 (reference), or ≥28.0 mEq/L (5,087, 4,330, 3,451, and 2,264 patients, respectively).
  
  
  RESULTS
  All-cause and cardiovascular (CV) mortality during the 1-year follow-up.
  
  
  METHODS
  HRs were estimated using unadjusted models and models adjusted for age, sex, dialysis vintage, history of CV disease, diabetes, weight gain ratio, body mass index, calcium-phosphorus product, serum albumin level, serum total cholesterol level, blood hemoglobin level, single-pool Kt/V, and normalized protein catabolic rate.
  
  
  RESULTS
  Of 15,132 patients, during follow-up, 1,042 died of all causes, including 408 CV deaths. In the adjusted analysis for all-cause mortality, HRs compared to the reference group were significantly higher in patients with predialysis pH≥7.40 (HR, 1.36; 95% CI, 1.13-1.65) and postdialysis pH<7.40 (HR, 1.22; 95% CI, 1.00-1.49). Predialysis pH≥7.40 was also associated with higher risk of CV mortality (HR, 1.34; 95% CI, 1.01-1.79). No association of pre- or postdialysis bicarbonate level with all-cause and CV mortality was observed.
  
  
  CONCLUSIONS
  Single measurements of acid-base parameters, short duration of follow-up, small number of CV deaths.
  
  
  CONCLUSIONS
  Predialysis pH≥7.40 was associated with significantly elevated risk of all-cause and CV mortality. However, pre- and postdialysis bicarbonate levels were not associated with all-cause and CV mortality. Predialysis pH may be the most appropriate reference for accurate correction of metabolic acidosis in dialysis patients.
authors.affiliation: Kidney Center, Shirasagi Hospital, Osaka, Japan. Electronic address: yamamoto@shirasagi-hp.or.jp.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Yamamoto
authors.affiliation: Kidney Center, Shirasagi Hospital, Osaka, Japan.
authors.forename: Shigeichi
authors.initials: S
authors.lastname: Shoji
authors.affiliation: Kidney Center, Shirasagi Hospital, Osaka, Japan.
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yamakawa
authors.affiliation: Committee of Renal Data Registry of the Japanese Society for Dialysis Therapy, Tokyo, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Wada
authors.affiliation: Committee of Renal Data Registry of the Japanese Society for Dialysis Therapy, Tokyo, Japan.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Committee of Renal Data Registry of the Japanese Society for Dialysis Therapy, Tokyo, Japan.
authors.forename: Kunitoshi
authors.initials: K
authors.lastname: Iseki
authors.affiliation: Committee of Renal Data Registry of the Japanese Society for Dialysis Therapy, Tokyo, Japan.
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Tsubakihara
mesh_terms: D000368:Aged; D002318:Cardiovascular Diseases / Q000401:mortality*; D002423:Cause of Death; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007676:Kidney Failure, Chronic / Q000401:mortality* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D006435:Renal Dialysis / Q000401:mortality*; D018570:Risk Assessment; D017693:Sodium Bicarbonate / Q000097:blood*
chemical_list: D017693:Sodium Bicarbonate
keywords: Japanese Renal Data Registry (JRDR); Predialysis pH; acid-base status; all-cause mortality; cardiovascular mortality; dialysate bicarbonate; end-stage renal disease (ESRD); hemodialysis; metabolic acidosis; postdialysis pH; renal replacement therapy; serum bicarbonate