Comparison of intradialytic blood pressure metrics as predictors of all-cause mortality

BACKGROUND: Intradialytic hypotension (IDH) has been reported to be an important prognostic factor in hemodialysis patients. However, a standard definition of IDH has not yet been determined. METHODS: We retrospectively analyzed blood pressure (BP) metrics obtained during serial dialysis sessions over a 90-day period from a single dialysis center from 2016 to 2017. The mean values and the frequency of specific values of BP were analyzed as predictors of 3-year mortality. RESULTS: A total of 430 patients who underwent maintenance dialysis were included. The mean age was 63.3 ± 12.4 years and 58.6% were male. A low minimum systolic blood pressure (SBP) <110 mmHg during dialysis was significantly associated with increased all-cause mortality. The frequency of a minimum SBP <100 mmHg was the most significant predictor of 3-year mortality, with an area under the curve (AUC) of 0.722. Furthermore, the frequency of a minimum SBP <100 mmHg significantly increased the predictability of mortality when combined with the presence of other clinical factors including age, body mass index and vascular access type (AUC 0.786 vs. 0.835; p = 0.005). CONCLUSION: Among the various intradialytic BP metrics, the frequency of a minimum SBP <100 mmHg is the most significant factor related to all-cause mortality. The guidelines for the management of blood pressure in dialysis patients should consider including a minimum SBP <100 mmHg as a definition for IDH.