Impact of fluid overload on blood pressure variability in patients on peritoneal dialysis

Fluid overload is a common complication in patients who are on continuous ambulatory peritoneal dialysis (CAPD). Blood pressure is the traditional indicator of fluid status in these patients. However, it has poor sensitivity. Blood pressure variability (BPV) can detect fluctuations in blood pressure sooner and more accurately and be useful for the assessment of fluid volume in hemodialysis patient. However, there are limited relevant studies involving patients on CAPD. This retrospective study included 175 patients on CAPD who underwent regular assessment of the peritoneal dialysis adequacy at 2-3-month intervals at our center from January 2018 to December 2020. The overhydration (OH) value was measured using a body composition monitor. Blood pressure measurements obtained in each visit over one-year follow-up were used to determine each patient's BPV under peritoneal dialysis. The patients were divided into the normal volume (OH ≤2 L), mild volume overload (OH 2-4 L), and severe volume overload groups (OH ≥4 L). There was no significant between-group difference in the mean blood pressure (p > 0.05). However, the systolic and diastolic BPV values were significantly higher in the severe volume overload group than in the other groups (p < 0.05). Further correlation and regression analysis showed volume overload severity and BPV existed positive association, and BPV was also significantly associated with PD volume related indexes, including diabetes mellitus, blood parathyroid hormone levels, Kt/V and subjective global assessment scores in the volume overloaded group (p < 0.05). All these results suggested BPV may be a useful indicator for fluid status in PD patients.