Abstract: Objective To observe the influence of interdialytic weight gain (IDWG) variation on prognosis in maintenance hemodialysis (MHD) patients. Methods The general information, laboratory indicators and patient outcomes of 229 MHD patients during October 2018 to October 2021 were recruited from the Department of Nephrology, Minhang Hospital, Fudan University. According to the interdialytic weight gain coefficient of variation (IDWG-CV), patients were divided into three groups: high IDWG variation group (IDWG-CV average of 0.617), moderate IDWG variation group (IDWG-CV average of 0.345) and low IDWG variation group (IDWG-CV average of 0.231). The relationship between IDWG-CV and all-cause mortality and cardiovascular disease mortality was analyzed. Results In the 229 MHD patients, the mean age was 61.79±14.47 years, the mean age of dialysis was 58.93±21.10 months (95% CI: 56.187～61.682), and 55 patients (24%) died, among which 24 patients (10.5%) died of cardiovascular diseases. The all-cause mortality
in the high IDWG variation group was higher than that in the moderate and low IDWG variation groups but without statistical significance (31.6% vs. 24.7% vs. 15.8%, χ2=5.219, P=0.074). The cardiovascular disease mortality in the high IDWG variation group was also higher than that in the moderate and low IDWG variation groups (18.4% vs. 9.1% vs. 3.9%, χ2=8.724, P=0.013). Subgroup of the patients based on whether IDWG variation of the patient was in the target range showed that all-cause mortality and cardiovascular disease mortality were higher in the patients with higher IDWG variation out of the target range than in the patients in other 5 groups (For all- cause mortality: 51.4% vs. 14.6%, 40.0%, 17.3%, 33.3% and 6.1%; χ2=22.351, 2.030,
11.379, 0.765 and 11.831; P＜0.001, 0.154, 0.001, 0.382 and 0.001. For cardiovascular disease mortality: 31.4% vs. 7.3%, 16.0%, 5.8%, 3.7% and 4.1%; χ2=11.672, 7.506, 10.201, 1.851 and 7.305; P=0.001, 0.006, 0.001, 0.174 and 0.007). COX regression showed that advanced age (HR=2.365, 95% CI: 1.160～4.822, P=0.018), oliguria (HR=0.525, 95% CI: 0.284～0.972, P=0.040), hypoproteinemia (HR=0.291, 95% CI: 0.162～0.522, P＜0.001) and higher IDWG (HR=3.385, 95% CI: 1.909～6.002, P＜0.001) were the independent risk factors for all- cause mortality in MHD patients; hypoproteinemia (HR=0.223, 95% CI: 0.087～ 0.575, P=0.002) and higher IDWG (HR=3.318, 95% CI: 1.387～7.940, P=0.007) were the independent risk
factors for cardiovascular disease mortality in MHD patients. Kaplan-Meier survival analysis showed that the patients with IDWG variation not in the target range had higher all-cause mortality and cardiovascular disease mortality than those with IDWG variation in the target range (χ2=26.570 and 10.423, P＜0.001 and 0.001). The patients with higher IDWG variation had higher all-cause mortality and cardiovascular disease mortality than those with moderate and low IDWG variation (χ2=7.116 and 10.097, P=0.028 and 0.006).  Conclusions MHD patients with higher IDWG variation have higher all-cause mortality and cardiovascular disease mortality. Patients with higher IDWG variation out of the target range have a higher mortality. Control of the IDWG variation within the target range and with low IDWG variation may be beneficial in improving survival rate in MHD patients.

Key words: Interdialytic weight gain, Variation, Maintenance hemodialysis