title: Relationship between interdialytic weight gain and blood pressure among prevalent hemodialysis patients.
abstract: BACKGROUND
  Hypertension is common in hemodialysis patients; however, the relationship between interdialytic weight gain (IDWG) and blood pressure (BP) is incompletely characterized. This study seeks to define the relationship between IDWG and BP in prevalent hemodialysis subjects.
  
  
  METHODS
  This study used data from 32,295 dialysis sessions in 442 subjects followed up for 6 months in the Crit-Line Intradialytic Monitoring Benefit (CLIMB) Study.
  
  
  METHODS
  Mixed linear regression was used to analyze the relationship between percentage of IDWG (IDWG [%] = [current predialysis weight - previous postdialysis weight]/dry weight * 100) as the independent variable and systolic BP (SBP) and predialysis - postdialysis SBP (deltaSBP) as dependent variables.
  
  
  RESULTS
  In unadjusted analyses, every 1% increase in percentage of IDWG was associated with a 1.00 mm Hg (95% confidence interval [CI], +/-0.24) increase in predialysis SBP (P < 0.0001), 0.65 mm Hg (95% CI, +/-0.24) decrease in postdialysis SBP (P < 0.0001), and 1.66 mm Hg (95% CI, +/-0.25) increase in deltaSBP (P < 0.0001). After controlling for other significant predictors of SBP, every 1% increase in percentage of IDWG was associated with a 1.00 mm Hg (95% CI, +/-0.24) increase in predialysis SBP (P < 0.0001) and a 1.08 mm Hg (95% CI, +/-0.22) increase in deltaSBP with hemodialysis (P < 0.0001). However, in subjects with diabetes as the cause of end-stage renal disease, subjects with lower creatinine levels, and older subjects, the magnitude of the association between percentage of IDWG and predialysis SBP was less pronounced. The magnitude of percentage of IDWG on deltaSBP was less pronounced in younger subjects and subjects with lower dry weights. Results were similar with diastolic BP.
  
  
  CONCLUSIONS
  Hemodialysis BP measurements are imprecise estimates of BP and true hemodynamic burden in dialysis subjects.
  
  
  CONCLUSIONS
  In prevalent hemodialysis subjects, increasing percentage of IDWG is associated with increases in predialysis BP and BP changes with hemodialysis; however, the magnitude of the relationship is modest and modified by other clinical factors. Thus, although overall volume status may impact on BP to a greater extent, day-to-day variations in weight gain have a modest role in BP increases in prevalent subjects with end-stage renal disease.
authors.affiliation: Department of Medicine, Duke University Medical Center, Durham, NC 27705, USA. inrig001@mc.duke.edu
authors.forename: Jula K
authors.initials: JK
authors.lastname: Inrig
authors.forename: Uptal D
authors.initials: UD
authors.lastname: Patel
authors.forename: Barbara S
authors.initials: BS
authors.lastname: Gillespie
authors.forename: Vic
authors.initials: V
authors.lastname: Hasselblad
authors.forename: Jonathan
authors.initials: J
authors.lastname: Himmelfarb
authors.forename: Donal
authors.initials: D
authors.lastname: Reddan
authors.forename: Robert M
authors.initials: RM
authors.lastname: Lindsay
authors.forename: James F
authors.initials: JF
authors.lastname: Winchester
authors.forename: John
authors.initials: J
authors.lastname: Stivelman
authors.forename: Robert
authors.initials: R
authors.lastname: Toto
authors.forename: Lynda A
authors.initials: LA
authors.lastname: Szczech
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology*; D001811:Blood Volume Determination / Q000295:instrumentation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000150:complications / Q000503:physiopathology; D007676:Kidney Failure, Chronic / Q000150:complications / Q000503:physiopathology / Q000628:therapy; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D006435:Renal Dialysis; D015430:Weight Gain / Q000502:physiology*