Changes in pre-dialysis blood pressure variability in the first year of dialysis associate with mortality in European hemodialysis patients: a retrospective cohort study on behalf of the MONDO Initiative.

Abstract

Pre-hemodialysis systolic blood pressure variability (pre-HD SBPV) has been associated with outcomes. The association of a change in pre-HD SBPV over time with outcomes, and predictors of this change, has not yet been studied. Therefore, we studied this in a cohort of 8825 incident hemodialysis (HD) patients from the European Monitoring Dialysis Outcomes Initiative database. Patient level pre-HD SBPV was calculated as the standard deviation of the residuals of a linear regression model of systolic blood pressure (SBP) over time divided by individual mean SBP in the respective time periods. The pre-HD SBPV difference between months 1-6 and 7-12 was used as an indicator of pre-HD SBPV change. The association between pre-HD SBPV change and all-cause mortality in year 2 was analyzed by multivariate Cox models. Predictors of pre-HD SBPV change was determined by logistic regression models. We found the highest pre-HD SBPV tertile, in the first 6 months after initiation of HD, had the highest mortality rates (adjusted HR 1.44 (95% confidence intervals (95% CI): 1.15-1.79)). An increase in pre-HD SBPV between months 1-6 and 7-12 was associated with an increased risk of mortality in year 2 (adjusted HR 1.29 (95% CI: 1.05-1.58)) compared with stable pre-HD SPBV. A pre-HD SBPV increase was associated with female gender, higher mean pre-HD SBP and pulse pressure, and lower HD frequency.