title: Changing relationship of blood pressure with mortality over time among hemodialysis patients.
abstract: High BP is a major risk factor for atherosclerotic cardiovascular disease mortality in the general population. Surprising, studies that have been conducted among hemodialysis (HD) patients have yielded conflicting data on the relationship between BP and mortality. This study explores two hypotheses among HD patients: (1) The relationship between BP and mortality changes over time, and (2) mild to moderate hypertension is well tolerated. Incident HD patients who were treated at Dialysis Clinic Inc. facilities between 1993 and 2003 were studied. Primary end points were atherosclerotic cardiovascular disease and all-cause mortality. The relationship between BP and mortality was analyzed in two sets of Cox proportional hazards models. Model-B explored the relationship between baseline BP and mortality in sequential time periods. Model-TV assessed the relationship between BP, treated as time-varying, and mortality. The study sample (n = 16,959) was similar in characteristics to the United States Renal Data Systems population, although black patients were slightly overrepresented. Model-B demonstrated that the relationship between baseline BP and mortality changes over time. Low systolic BP (<120 mmHg) was associated with increased mortality in years 1 and 2. High systolic BP (> or =150 mmHg) was associated with increased mortality among patients who survived > or =3 yr. Low pulse pressure was associated with increased mortality. Model-TV demonstrated that mild to moderate systolic hypertension may be relatively well tolerated. In conclusion, the relationship between baseline BP and mortality changes over time. Mild to moderate systolic hypertension was associated with only modest increases in mortality.
authors.affiliation: University of New Mexico, Department of Internal Medicine, ACC 5, MSC 10-5550, Albuquerque, NM 87131, USA.
authors.forename: Christine A
authors.initials: CA
authors.lastname: Stidley
authors.forename: William C
authors.initials: WC
authors.lastname: Hunt
authors.forename: Francesca
authors.initials: F
authors.lastname: Tentori
authors.forename: Darren
authors.initials: D
authors.lastname: Schmidt
authors.forename: Mark
authors.initials: M
authors.lastname: Rohrscheib
authors.forename: Susan
authors.initials: S
authors.lastname: Paine
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Bedrick
authors.forename: Klemens B
authors.initials: KB
authors.lastname: Meyer
authors.forename: H Keith
authors.initials: HK
authors.lastname: Johnson
authors.forename: Philip G
authors.initials: PG
authors.lastname: Zager
mesh_terms: D000328:Adult; D000368:Aged; D050197:Atherosclerosis / Q000150:complications / Q000401:mortality* / Q000503:physiopathology*; D001794:Blood Pressure / Q000502:physiology*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications; D007676:Kidney Failure, Chronic / Q000150:complications / Q000401:mortality* / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D006435:Renal Dialysis; D012189:Retrospective Studies; D012720:Severity of Illness Index