title: Changes in pulse pressure during hemodialysis treatment and survival in maintenance dialysis patients.
abstract: OBJECTIVE
  Pulse pressure has been shown as a risk factor for mortality in patients on maintenance hemodialysis (MHD). However, the effect of change in pulse pressure during hemodialysis on survival in a large cohort of patients on MHD has not been sufficiently investigated.
  
  
  METHODS
  This study examined the association between time-varying Δ pulse pressure (postdialysis minus predialysis pulse pressure) and mortality in a cohort of 98,577 patients on MHD (July 2001-June 2006) using Cox proportional hazard models with restricted cubic splines.
  
  
  RESULTS
  The average patient age was 62 years old; among the patients, 33% were black and 59% had diabetes. During 134,814 patient-years of at-risk time, 16,054 (16%) patients died, with 6827 (43%) of the deaths caused by cardiovascular causes. In the models including adjustment for either predialysis systolic BP or mean arterial BP, there was a U-shaped association between change in pulse pressure during hemodialysis and all-cause mortality. In the systolic BP plus case mix plus malnutrition-inflammation complex syndrome-adjusted model, large declines in pulse pressure (>-25 mmHg) and increases in pulse pressure >5 mmHg were associated with higher all-cause mortality (reference: ≥-5 to <5 mmHg): hazard ratios (95% confidence intervals [95% CIs]) for change pulse pressures of <-25, ≥-25 to <-15, ≥-15 to <-5, 5 to <15, 15 to <25, and ≥25 mmHg were 1.21 (95% CI, 1.14 to 1.29), 1.03 (95% CI, 0.97 to 1.10), 1.01 (95% CI, 0.96 to 1.06), 1.06 (95% CI, 1.01 to 1.11), 1.17 (95% CI, 1.11 to 1.24), and 1.15 (95% CI, 1.08 to 1.23), respectively. The U-shaped association was observed with cardiovascular death.
  
  
  CONCLUSIONS
  Modest reductions in pulse pressure after hemodialysis are associated with the greatest survival, whereas large declines or rises in pulse pressure are related to higher mortality. Trials determining how to modify pulse pressure response to improve survival in the hemodialysis population are indicated.
authors.affiliation: Harold Simmons Center for Kidney Disease Research and Epidemiology, Orange, California; Chonprathan Hospital, Srinakharinwirot University, Nonthaburi, Thailand;
authors.forename: Paungpaga
authors.initials: P
authors.lastname: Lertdumrongluk
authors.affiliation: Harold Simmons Center for Kidney Disease Research and Epidemiology, Orange, California;
authors.forename: Elani
authors.initials: E
authors.lastname: Streja
authors.affiliation: Harold Simmons Center for Kidney Disease Research and Epidemiology, Orange, California; School of Medicine, University of California, Irvine, Orange, California;
authors.forename: Connie M
authors.initials: CM
authors.lastname: Rhee
authors.affiliation: Division of Nephrology and Hypertension, Kaiser Permanente Medical Center, Los Angeles, California;
authors.forename: John J
authors.initials: JJ
authors.lastname: Sim
authors.affiliation: Department of Statistics, University of California, Irvine, Irvine, California;
authors.forename: Daniel
authors.initials: D
authors.lastname: Gillen
authors.affiliation: Nephrology Section, Memphis Veterans Affairs Medical Center, Memphis, Tennessee; and Division of Nephrology, University of Tennessee Health Science Center, Memphis, Tennessee.
authors.forename: Csaba P
authors.initials: CP
authors.lastname: Kovesdy
authors.affiliation: Harold Simmons Center for Kidney Disease Research and Epidemiology, Orange, California; School of Medicine, University of California, Irvine, Orange, California; kkz@uci.edu.
authors.forename: Kamyar
authors.initials: K
authors.lastname: Kalantar-Zadeh
mesh_terms: D000368:Aged; D001794:Blood Pressure; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000209:etiology* / Q000401:mortality / Q000503:physiopathology; D002423:Cause of Death; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000150:complications / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D006435:Renal Dialysis / Q000009:adverse effects / Q000401:mortality; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology; D059289:Vascular Stiffness
keywords: hemodialysis; hemodynamics and vascular regulation; survival