title: A low serum bicarbonate concentration as a risk factor for mortality in peritoneal dialysis patients.
abstract: OBJECTIVE
  Metabolic acidosis is common in patients with chronic kidney disease and is associated with increased mortality in hemodialysis patients. However, this relationship has not yet been determined in peritoneal dialysis (PD) patients.
  
  
  METHODS
  This prospective observational study included a total of 441 incident patients who started PD between January 2000 and December 2005. Using time-averaged serum bicarbonate (TA-Bic) levels, we aimed to investigate whether a low serum bicarbonate concentration can predict mortality in these patients.
  
  
  RESULTS
  Among the baseline parameters, serum bicarbonate level was positively associated with hemoglobin level and residual glomerular filtration rate (GFR), while it was negatively associated with albumin, C-reactive protein (CRP) levels, peritoneal Kt/V urea, and normalized protein catabolic rate (nPCR) in a multivariable linear regression analysis. During a median follow-up of 34.8 months, 149 deaths were recorded. After adjustment for age, diabetes, coronary artery disease, serum albumin, ferritin, CRP, residual GFR, peritoneal Kt/V urea, nPCR, and percentage of lean body mass, TA-Bic level was associated with a significantly decreased risk of mortality (HR per 1 mEq/L increase, 0.83; 95% CI, 0.76-0.91; p < 0.001). In addition, compared to patients with a TA-Bic level of 24-26 mEq/L, those with a TA-Bic level < 22 and between 22-24 mEq/L conferred a 13.10- and 2.13-fold increased risk of death, respectively.
  
  
  CONCLUSIONS
  This study showed that a low serum bicarbonate concentration is an independent risk factor for mortality in PD patients. This relationship between low bicarbonate levels and adverse outcome could be related to enhanced inflammation and a more rapid loss of RRF associated with metabolic acidosis. Large randomized clinical trials to correct acidosis are warranted to confirm our findings.
authors.affiliation: Department of Internal Medicine, NHIS Medical Center, Ilsan Hospital, Goyangshi, Gyeonggi-do, Republic of Korea.
authors.forename: Tae Ik
authors.initials: TI
authors.lastname: Chang
authors.affiliation: Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea.
authors.forename: Hyung Jung
authors.initials: HJ
authors.lastname: Oh
authors.affiliation: Department of Internal Medicine, NHIS Medical Center, Ilsan Hospital, Goyangshi, Gyeonggi-do, Republic of Korea.
authors.forename: Ea Wha
authors.initials: EW
authors.lastname: Kang
authors.affiliation: Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea.
authors.forename: Tae-Hyun
authors.initials: TH
authors.lastname: Yoo
authors.affiliation: Department of Internal Medicine, NHIS Medical Center, Ilsan Hospital, Goyangshi, Gyeonggi-do, Republic of Korea.
authors.forename: Sug Kyun
authors.initials: SK
authors.lastname: Shin
authors.affiliation: Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea ; Brain Korea 21 for Medical Science, Severance Biomedical Science Institute, Yonsei University, Seoul, Republic of Korea.
authors.forename: Shin-Wook
authors.initials: SW
authors.lastname: Kang
authors.affiliation: Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea.
authors.forename: Kyu Hun
authors.initials: KH
authors.lastname: Choi
authors.affiliation: Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea.
authors.forename: Dae Suk
authors.initials: DS
authors.lastname: Han
authors.affiliation: Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea.
authors.forename: Seung Hyeok
authors.initials: SH
authors.lastname: Han
mesh_terms: D000328:Adult; D000368:Aged; D001639:Bicarbonates / Q000097:blood*; D002097:C-Reactive Protein / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis / Q000401:mortality*; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000401:mortality*; D012307:Risk Factors; D012709:Serum Albumin / Q000378:metabolism
chemical_list: D001639:Bicarbonates; D012709:Serum Albumin; D002097:C-Reactive Protein