Blood pressure variability and outcomes in chronic kidney disease

We investigated the effects of visit-to-visit systolic blood pressure variability (SBPV) on both mortality and dialysis inception in a cohort of chronic kidney disease (CKD) patients not requiring dialysis therapy. Furthermore, we also explored the carry-over effect of visit-to-visit SBPV on mortality after dialysis initiation. We conducted a longitudinal retrospective, observational, multi-centre study in three tertiary care nephrology outpatient clinics. All the ambulatory CKD patients admitted to the outpatient clinics from 1 January 2004 to 31 December 2005 were screened for study eligibility. We selected all consecutive patients older than 18 years of age with a mean estimated glomerular filtration rate of 60 mL/min/m(2), free from cardiovascular disease. SBPV was defined as the ratio of the SD to the mean SBP of five values recorded during a run-in phase of 45 months. Data on dialysis inception and mortality were recorded through 31 December 2010. Overall, we selected a cohort of 374 elderly (median age: 79 years) subjects. A total of 232 (62) and 103 (29) patients were male and had diabetes, respectively. A significant association between SBPV and the risk of death but not of CKD progression to dialysis was noted at univariate and after multivariable adjustments (hazard ratio for all-cause mortality per 1 increase in SBPV: 1.05; 95 confidence interval: 1.021.09; P 0.001). Notably, no lethal event was recorded after dialysis initiation. Current findings suggest that SBPV may be of use for risk stratification in CKD patients.