title: Absolute interdialytic weight gain is more important than percent weight gain for intradialytic hypotension in heavy patients.
abstract: OBJECTIVE
  Few published reports have mentioned the difference between absolute interdialytic weight gain (IDWG) and IDWG/DW (IDWG%), and subsequent effects on daily dialysis. The aim of present study was to evaluate the difference between absolute IDWG and IDWG% in new haemodialysis patients.
  
  
  METHODS
  We retrospectively reviewed the records of 255 patients who recently received conventional haemodialysis for at least 1 year at the same centre from 1997 to 2008. The first 4 weeks after starting haemodialysis was defined as the pre-study period. Data were collected for 5-56 weeks.
  
  
  RESULTS
  IDWG% value remained relatively constant in the first year of haemodialysis despite most patients having certain residual renal function. For haemodialysis outcomes, both absolute IDWG and IDWG% were significantly correlated with intradialytic hypotension (IDH) in men and heavy women. After dividing patients into four strata, which according to the gender and the median dry weight, stepwise multivariate linear regression analysis showed that absolute IDWG, rather than IDWG%, was an independent risk factor for IDH in heavy men (Beta = 0.585, P < 0.001) and heavy women (Beta= 0.458, P < 0.001).
  
  
  CONCLUSIONS
  Absolute IDWG, rather than IDWG%, is an independent risk factor for IDH in heavy haemodialysis patients. Therefore, higher absolute IDWG needs to be strictly controlled despite the corresponding IDWG% possibly being relatively small in heavy haemodialysis patients.
authors.affiliation: Divisions of Nephrology Hemodialysis Center, Department of Internal Medicine, Mackay Memorial Hospital, Taipei, Taiwan.
authors.forename: Chuan-Tsai
authors.initials: CT
authors.lastname: Lai
authors.forename: Chih-Jen
authors.initials: CJ
authors.lastname: Wu
authors.forename: Han-Hsiang
authors.initials: HH
authors.lastname: Chen
authors.forename: Chi-Feng
authors.initials: CF
authors.lastname: Pan
authors.forename: Chin-Ling
authors.initials: CL
authors.lastname: Chiang
authors.forename: Chiung-Ying
authors.initials: CY
authors.lastname: Chang
authors.forename: Yu-Wei
authors.initials: YW
authors.lastname: Chen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D005260:Female; D006801:Humans; D007022:Hypotension / Q000209:etiology*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis; D012189:Retrospective Studies; D012307:Risk Factors; D015430:Weight Gain