Abstract: Objective To explore the relationship between predialysis bicarbonate concentration and clinical characteristics in maintenance hemodialysis (MHD) patients. Methods A total of 291 MHD patients treated in our dialysis center were enrolled in this study. Their dialysis data and routine blood tests were collected. Patients were assigned into 4 groups according to the average bicarbonate concentration before dialysis by a quartile method, and clinical characteristics were then compared among the 4 groups. Pearson's correlation analysis was used to explore the relationship between predialysis bicarbonate concentration and clinical indicators, using predialysis bicarbonate concentrations as the dependent variables. Analysis of variance (ANOVA) was used for the analyses of measurement data, and chi square test was used for the analyses of count data. P＜0.05 was considered to be statistically significant. Results There were differences among the 4 groups in duration of dialysis (F=3.527, P=0.015), ratio of twice weekly dialysis (χ2=3.527, P=0.015), body mass index (BMI) (F=5.000, P=0.002), serum albumin (F=7.336, P＜0.001), serum creatinine (F=4.932, P=0.002), serum calcium (F=2.969, P=0.032), and serum phosphorus (F=13.468, P＜0.001). Pearson's correlation analyses demonstrated that predialysis bicarbonate concentration was negatively correlated with duration of dialysis (r=-0.118, P=0.022), BMI (r=-0.153, P=0.004), serum albumin (r=-0.285, P＜0.001), serum creatinine (r=-0.213, P＜0.001), serum phosphorus (r=-0.378, P＜0.001), and iPTH (r=-0.129, P=0.014), and was positively correlated with serum calcium (r=0.113, P= 0.027) in these MHD patients. Conclusions In MHD patients with stable clearance of solution and similar ratio of required hemoglobin concentration, those with lower predialysis bicarbonate concentration had the characteristics of longer dialysis duration, higher ratio of twice weekly dialysis, larger BMI, higher concentration of serum albumin, creatinine and phosphorus, and lower serum calcium.

Key words: Maintenance hemodialysis, Metabolic acidosis, Bicarbonate concentration