Visit-to-Visit Variability in Systolic Blood Pressure Is a Risk Factor for Rapid Loss of Residual Renal Function in Peritoneal Dialysis Patients

Visit-to-visit systolic blood pressure variability (VTV-SBPV) is correlated with cardiovascular complications. However, it still remains unclear whether VTV-SBPV is related to cardiovascular outcomes in patients with peritoneal dialysis (PD), who often manifest hypertension. We, therefore, evaluated the association of VTV-SBPV with all-cause mortality, cardiovascular complications, or the loss of residual renal function (RRF) that is a powerful predictor of mortality and morbidity in PD patients. We retrospectively reviewed the medical records for patients undergoing maintenance PD for at least 12 months at Seoul National University Hospital. The patients were divided into quartiles of VTV-SBPV based on the standard deviation of systolic blood pressure (SBP). We checked the SBP of the patients for up to 2 years after the initiation of PD. Among 216 PD patients, 16 primary outcome events (cardiovascular complications and all-cause mortality) occurred. VTV-SBPV was not associated with primary outcomes. During the follow-up, RRF loss occurred in 46 patients. The hazard ratios (HRs) for the loss of RRF in the 4 quartiles of VTV-SBPV, based on the highest to the lowest variability, were as follows: 6.201 (95% Cl: 1.982-19.401, p = 0.002), 2.542 (95% Cl: 0.859-7.523, p = 0.092), and 2.133 (95% Cl: 0.635-7.165, p = 0.246), respectively. The loss of RRF was more frequently detected in patients with higher VTV-SBPV. VTV-SBPV was indicated as an independent risk factor for the loss of RRF. Therefore, the degree of variations in SBP should be carefully monitored to preserve the RRF of these patients.