P1159MILD BLOOD PRESSURE VARIABILITY IS ASSOCIATED WITH BETTER SURVIVAL IN PATIENTS WITH END STAGE RENAL DISEASE AND PERITONEAL DIALYSIS

Abstract Background and Aims Recently, variability in blood pressure (BP) has been recognized as a risk factor for mortality and cardiovascular events in the general population. However, most studies included patients with normal or near normal kidney function. Aim To study the association between BP variability and the risk of all-cause mortality in patients with end stage renal disease (ESRD) and peritoneal dialysis (PD) treatment. Method From 2008 until the end of 2017, 2329 patients with ESRD and at least three months of PD (mean age: 63.8 years, men: 67.5%) were followed for 16 months in median (interquartile range: 11-28 months). Data were extracted from the Swedish Renal Register (SNR). The coefficient variation (CV = the ratio of the standard deviation (SD) to the mean value) was defined as BP variability in terms of systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) [SBP(SD)/SBP(mean), DBP(SD)/ DBP(mean), and MAP(SD)/MAP(mean), respectively]. The relationships between BP variability and mortality were examined by time-dependent Cox models to estimate hazard ratios (HR) and 95% confidence intervals (CI) in univariate and multivariate analyses, with adjustment for demographics, laboratory findings and comorbidity. Results During the follow-up period, 1054 (45%) deaths occurred. The mean level of BP variability was CV=0.10± 0.1. The highest rate of mortality was observed in the patients with the highest variability in SBP (CV>0.25; 64% of those patients died). In the multivariate model, for each of the BP variables, we compared the risk of mortality in the lowest variability group (CV≤ 0.05) with that in the CV=0.10-0.15 group (reference): SBP: (HR 1.74, 95% CI 1.44- 2.09; p<0.001); DBP: (HR 1.91, 95% CI 1.59- 2.23; p<0.001); and MAP: (HR 1.73, 95% CI 1.44- 2.06; p<0.001). Thus, for all BP variables, the lowest variability was associated with increased mortality risk. We then compared the highest variability group (CV>0.25) with the CV=0.10-0.15 group (reference): SBP: (HR 1.60, 95% CI 1.14- 2.25; p<0.001); DPB: (HR 1.74, 95% CI 1.44- 2.09; p<0.001); and MAP: (HR 1.98, 95% CI 1.21- 3.27; p<0.001). Thus, for all BP variables, the highest variability was related to increased mortality risk. Conclusion In this study, the association between BP variability and the risk of mortality was U-shaped in patients with ESRD and PD. Thus, both very low and high levels of BP variability were related to higher risk of mortality. Mild BP variability was associated with the lowest risk of mortality, which could suggest that, non-intensive and long duration of ultrafiltration (UF) with PD was probably beneficial in terms of survival