Pre-dialysis systolic blood pressure-variability is independently associated with all-cause mortality in incident haemodialysis patients.
Systolic blood pressure variability is an independent risk factor for mortality and cardiovascular events. Standard measures of blood pressure predict outcome poorly in haemodialysis patients. We investigated whether systolic blood pressure variability was associated with mortality in incident haemodialysis patients. We performed a longitudinal observational study of patients commencing haemodialysis between 2005 and 2011 in East Anglia, UK, excluding patients with cardiovascular events within 6 months of starting haemodialysis. The main exposure was variability independent of the mean (VIM) of systolic blood pressure from short-gap, pre-dialysis blood pressure readings between 3 and 6 months after commencing haemodialysis, and the outcome was all-cause mortality. Of 203 patients, 37 (18.2%) patients died during a mean follow-up of 2.0 (SD 1.3) years. The age and sex-adjusted hazard ratio (HR) for mortality was 1.09 (95% confidence interval (CI) 1.02-1.17) for a one-unit increase of VIM. This was not altered by adjustment for diabetes, prior cardiovascular disease and mean systolic blood pressure (HR 1.09, 95% CI 1.02-1.16). Patients with VIM of systolic blood pressure above the median were 2.4 (95% CI 1.17-4.74) times more likely to die during follow-up than those below the median. Results were similar for all measures of blood pressure variability and further adjustment for type of dialysis access, use of antihypertensives and absolute or variability of fluid intake did not alter these findings. Diastolic blood pressure variability showed no association with all cause mortality. Our study shows that variability of systolic blood pressure is a strong and independent predictor of all-cause mortality in incident haemodialysis patients. Further research is needed to understand the mechanism as this may form a therapeutic target or focus for management.
Clinical Pharmacology Unit, Department of Medicine, University of Cambridge, Cambridge, United Kingdom ; Department of Nephrology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom.
Viknesh
V
Selvarajah
Centre for Applied Medical Statistics, Department of Public Health and Primary Care, Institute of Public Health, University of Cambridge, Cambridge, United Kingdom.
Laura
L
Pasea
Department of Nephrology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, United Kingdom.
Sanjay
S
Ojha
Cambridge Clinical Trials Unit, University of Cambridge, Cambridge, United Kingdom.
Ian B
IB
Wilkinson
Cambridge Clinical Trials Unit, University of Cambridge, Cambridge, United Kingdom.
Laurie A
LA
Tomlinson
D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D002423:Cause of Death; D003710:Demography; D005260:Female; D006801:Humans; D008297:Male; D016016:Proportional Hazards Models; D006435:Renal Dialysis / Q000401:mortality*; D013599:Systole / Q000502:physiology*