Association Between Long-term Blood Pressure Variability and Mortality Among Incident Hemodialysis Patients
Received 30 December 2007; accepted 29 April 2008. published online 28 August 2008.
Refers to article:
Variations in Levels of Blood Pressure: Of Prognostic Value or Not?
Tazeen H. Jafar, Shah B.J. Ebrahim
American Journal of Kidney Diseases
October 2008 (Vol. 52, Issue 4, Pages 638-641) Full Text |
Full-Text PDF (70 KB)
Background
Blood pressure variability (BPV) is one putative risk factor for cardiovascular disease and mortality in hemodialysis patients. The purposes of this study are to identify a suitable metric of long-term BPV in this population and determine whether an association between BPV and all-cause mortality exists.
Study Design
Retrospective cohort study.
Settings & Participants
Patients from the Accelerated Mortality on Renal Replacement (ArMORR) cohort who were adult, incident to hemodialysis at any Fresenius Medical Care unit between June 2004 and August 2005, and had suitable blood pressure data were studied (n = 6,961).
Predictor
Predialysis blood pressures measured between dialysis days 91 and 180 were used to determine each patient's absolute level of, trend in (slope over time), and variability in blood pressure.
Outcome
All-cause mortality beginning immediately after day 180 and continuing through day 365 or until censoring (median follow-up, 185 days).
Results
Of the 4 candidate BPV metrics, only average residual-intercept ratio adequately distinguished BPV from absolute blood pressure level and temporal blood pressure trend. In the primary analysis, each SD increase in systolic and diastolic BPV was associated with adjusted hazard ratios for all-cause mortality of 1.13 (95% confidence interval, 1.03 to 1.23) and 1.15 (95% confidence interval, 1.06 to 1.26), respectively. Results were consistent across multiple sensitivity analyses in which inclusion and exclusion criteria and timing of blood pressure measurements were varied.
Limitations
Contingency of results on the validity of mathematic description of BPV; potential for misclassification bias and residual confounding.
Conclusions
Provided the mathematical descriptions of BPV are valid, the data suggest that systolic and diastolic BPV is associated with all-cause mortality in incident hemodialysis patients. Additional study is necessary to confirm and generalize findings, assess the interplay between systolic and diastolic BPV, and assess causality.
1Renal, Electrolyte, and Hypertension Division, University of Pennsylvania School of Medicine, Philadelphia, PA
2Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania School of Medicine, Philadelphia, PA
3Renal Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA
Address correspondence to Steven M. Brunelli, MD, MSCE, Center for Clinical Epidemiology and Biostatistics, 109 Blockley Hall, 423 Guardian Dr, Philadelphia, PA 19104
Because an author of this manuscript is an editor for AJKD, the peer-review and decision-making processes were handled entirely by an Associate Editor (Tazeen H. Jafar, MD, MPH, Aga Khan University) who served as Acting Editor-in-Chief. Details of the journal's procedures for potential editor conflicts are given in the Editorial Policies section of the AJKD website.
ABSTRACT