Abstract: Objective To evaluate intradialytic blood pressure variability (BPV) in patients on maintenance hemodialysis (MHD), and to investigate the related factors for BPV during MHD sessions. Methods A total of 182 MHD patients were divided into two groups according to the percentage of BPV (systolic blood pressure coefficient of variation, SBP- CV), high BPV group (SBP-CV ≥9.48) and low BPV group (SBPCV＜9.48). Associated factors for BPV were analyzed. To further study the relationship between inter-dialysis weight gain rate (IDWG%) and BPV, we defined the median IDWG% 4.1% as the cut-off value, and divided the patients into higher IDWG% group and lower IDWG% group. Results More females, more ultrafiltration volume, and higher IDWG% were found in the high BPV group (t=2.133 and P=0.048 for gender; t =2.667 and P =0.008 for ultrafiltration volume; t =2.265, P =0.025 for IDWG%). Lower levels of serum albumin (Alb) and LDL-C were found in the low BPV group (t=2.416 and P=0.017 for Alb; t=2.317 and P=0.022 for LDL-C). Multivariate regression analyses showed that BPV was positively correlated with IDWG%, Alb and diabetes (β=0.194 and P=0.008 for IDWG%; β=0.166 and P =0.023 for Alb; β=0.179 and P=0.015 for diabetes). Dialysis duration, phosphorus and PTH levels, SBP-CV, diastolic blood pressure coefficient of variation (DBP-CV) were significantly higher in the higher IDWG% group than in the lower IDWG% group (t =2.265 and P =0.025 for dialysis duration; t=3.763 and P＜0.001 for phosphorus; t =2.707 and P =0.007 for PTH, t = 3.831 and P＜0.001 for SBP-CV: t =2.087 and P =0.038 for DBP-CV), while age was younger in the higher IDWG% group (t =2.696, P =0.008). Conclusion IDWG% is an independent risk factor for BPV. Younger age, long dialysis duration, high levels of phosphorus and PTH are associated with higher IDWG%.
Control of IDWG% is an important method for the improvement of BPV in MHD patients.

Key words: hemodialysis, variability of blood pressure, interdialysis weight gain