Abstract: 【Abstract】Objective To investigate volume overload status before and after dialysis, and to analyze the factors relating to overhydration before dialysis in maintenance hemodialysis (MHD) patients. Methods The MHD patients treated in Hangzhou Traditional Chinese Medical Hospital from December 2017 to April 2018 were enrolled in this study. Clinical data and biochemical results were recruited. The hydration status index, i.e. overhydration (OH) value, was measured by using bioimpedance spectroscopy. Multivariate linear regression was used to analyze the independent factors associated with overhydration. Results Atotal of 196MHD patients were enrolled in this study. Before dialysis, 52 (27%) of the patients were of normal volume (-1.1L ≤ OH ≤ 1.1L); 144 (73%) of the patients were overhydrated (OH ＞1.1L), in which 89 (45%) patients were moderate volume overloaded (1.1L＜OH≤2.5L), 55 (28%) patients were severe volume overloaded (OH＞2.5L). After dialysis, 29 patients (15%) were still volume overloaded. Correlation study showed that gender (r=-0.322, P＜0.001), diabetes (r=0.432, P＜0.001), cardiovascular disease (r=0.346, P＜0.001), hypertension (r=0.166, P=0.020), Chalson comorbidity index (r=0.433, P＜0.001), systolic pressure (r= 0.266, P＜0.001), hemoglobin (r=-0.210, P=0.003), serum albumin (r=-0.211, P=0.003), fasting blood glucose (r=0.397, P＜0.001), urea clearance index (r=-0.287, P＜0.001), and high sensitive C reactive protein (r=0.202, P=0.005) were associated with OH value. Multivariate linear regression analyses showed that male (β=-0.580, P=0.001), diabetes (β=0.949, P＜0.001), cardiovascular disease (β=0.632, P=0.001), higher systolic pressure (β=0.014, P＜0.001), lower serumalbumin (β=-0.062, P=0.007), and lower fat tissue index (β=-0.073, P=0.003) were the independent factors relating to the increase of OH before dialysis. Conclusion Overhydration is frequently seen inMHD patients before dialysis. In this cohort of MHD patients, 73% patients were overhydrated and 28% patients were severely volume overloaded before dialysis. Therefore more attention should be paid to the volume overload status inMHD patients, especially in males and those with hypertension, diabetes, cardiovascular disease, lower serum albumin and lower fat tissue index. After dialysis, the volume overload status improved significantly in most patients and remained in 15% MHD patients.

Key words: Maintenance hemodialysis patients, Volume overload, Bioimpedance spectroscopy