Association between Serum Bicarbonate and Death in Hemodialysis Patients

Abstract
The optimal acid-base status for survival in maintenance hemodialysis (MHD) patients remains controversial. According to recent reports, acidosis is associated with improved survival in MHD patients. It was hypothesized that this inverse association is due to a confounding effect of the malnutrition-inflammation complex syndrome (MICS). Associations between baseline (first 3 mo averaged) predialysis serum bicarbonate (HCO3−) and 2-yr mortality were examined in 56,385 MHD patients who were treated in virtually all DaVita dialysis clinics across the United States. The range of HCO3− was divided into 12 categories (22 mEq/L had lower death risk. Although previous epidemiologic studies indicated an association between high serum HCO3− and increased mortality in MHD patients, this effect seems to be due substantially to the effect of MICS on survival.