Association between pulse pressure and mortality in patients undergoing maintenance hemodialysis.
BACKGROUND
Although increased blood pressure is associated with adverse outcomes in the general population, elevated blood pressure is associated with decreased mortality in patients with end-stage renal disease undergoing maintenance hemodialysis. Recent investigations in the general population have demonstrated the predictive utility of pulse pressure (systolic minus diastolic blood pressure), a measure reflecting the pulsatile nature of the cardiac cycle.


OBJECTIVE
To estimate the relationship between pulse pressure and mortality in patients undergoing maintenance hemodialysis and to test our hypothesis that an increasing pulse pressure would be associated with increased risk of death up to 1 year despite the inverse relationship between conventional blood pressure measures and mortality in patients with end-stage renal disease.


METHODS
Retrospective cohort investigation of patients with end-stage renal disease undergoing maintenance hemodialysis at 782 hemodialysis facilities throughout the United States. Of 44 069 eligible patients as of January 1, 1998, 37 069 with complete demographic data were included in the analyses of clinical and laboratory data collected from October 1 through December 31, 1997. Patients were followed up through December 31, 1998.


METHODS
The primary study outcome was death at 1 year. A secondary outcome was the magnitude of the pulse pressure.


RESULTS
The final patient cohort was similar to national averages with respect to age, sex, race, and diabetic status. Mean (SD) pulse pressures before dialysis were 75.0 (15.0) mm Hg and 66.9 (13.9) mm Hg after dialysis. By the end of the 1-year follow-up, 5731 patients (18.4%) died. After adjusting for level of systolic blood pressure, multivariable Cox proportional hazards modeling showed a direct and consistent relationship between increasing pulse pressure and increasing death risk. Each incremental elevation of 10 mm Hg in postdialysis pulse pressure was associated with a 12% increase in the hazard for death (hazard ratio, 1.12; 95% confidence interval, 1.06-1.18). Postdialysis systolic blood pressure was inversely related to mortality with a 13% decreased hazard for death for each incremental elevation of 10 mm Hg (hazard ratio, 0.87; 95% confidence interval, 0.84-0.90). In a multivariable linear regression model, important variables directly associated with elevated pulse pressure included age, diabetes, white race, female sex, and number of years receiving dialysis (all P<.001).


CONCLUSIONS
Pulse pressure is associated with risk of death in a large, nationally representative sample of patients undergoing maintenance hemodialysis. The recognition of pulse pressure as an important correlate of mortality in patients receiving dialysis highlights the need to investigate the relationship between potential therapeutic implications of conduit vessel function and clinical outcomes in patients with end-stage renal disease.
Klassen
Preston S
PS
Duke Institute of Renal Outcomes Research and Health Policy, Box 3646, Duke University Medical Center, Durham, NC 27710. klass001@mc.duke.edu
Lowrie
Edmund G
EG
Reddan
Donal N
DN
DeLong
Elizabeth R
ER
Coladonato
Joseph A
JA
Szczech
Lynda A
LA
Lazarus
J Michael
JM
Owen
William F
WF
D000367:Age Factors; D000368:Aged; D000704:Analysis of Variance; D001794:Blood Pressure / Q000502:physiology*; D048909:Diabetes Complications; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000401:mortality*; D007676:Kidney Failure, Chronic / Q000150:complications / Q000401:mortality* / Q000503:physiopathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D006435:Renal Dialysis; D012189:Retrospective Studies; D012307:Risk Factors