title: The effect of ambient temperature and humidity on interdialytic weight gains in end-stage renal disease patients on maintenance hemodialysis.
abstract: OBJECTIVE
  Interdialytic weight gain (IDWG) is both a measure of dietary compliance and a well-established predictor of future adverse outcomes in dialysis patients. The impact of environmental conditions on IDWG in end-stage renal disease is little studied to date.
  
  
  METHODS
  We retrospectively reviewed IDWG for 100 consenting chronic end-stage renal disease patients undergoing thrice weekly in-center hemodiafiltration under three different climatic conditions in a Central European city: Weekend_1 was humid (93 %) and warm (24 °C); Weekend_2 was dry (38 %) and hot (33 °C); and Weekend_3 was dry (30 %) and warm (24 °C).
  
  
  RESULTS
  The cohort's mean age was 60.9 ± 14.7 years, all were Eastern European, and 56 % were men. Residual urine output measured 100 [25-75 % quartiles: 0, 612] mL/day, single-pool Kt/V 1.4 ± 0.25, and albumin 40.1 ± 3.9 g/L. Mean IDWGs measured as follows: Weekend_1 ("humid-warm"): 2973 ± 1386 mL; Weekend_2 ("dry-hot"): 2685 ± 1368 mL and Weekend_3 ("dry-warm"): 2926 ± 1311 mL. Paired-samples testing for difference showed higher fluid gains on the humid-warm (239 mL; 95 % CI 21-458 mL; p = 0.032) and on the dry-warm weekends (222 mL; 95 % CI -8 to 453 mL, p = 0.059), when compared to the dry-hot weekend. Under the latter, dry-hot climatic condition, residual urine output lost its significance to impact IDWG during multiple regression analysis.
  
  
  CONCLUSIONS
  While excess temperature may impact IDWG to a small degree, air humidity does not; the least weight gains occurred on the dry-hot weekend. However, the effects of both were minimal under continental summer conditions and are unlikely to explain large excesses of individual session-to-session variations.
authors.affiliation: Fresenius Medical Care, Semmelweis University, Budapest, Hungary.
authors.forename: Mihály B
authors.initials: MB
authors.lastname: Tapolyai
authors.affiliation: Fresenius Medical Care, Semmelweis University, Budapest, Hungary.
authors.forename: Mária
authors.initials: M
authors.lastname: Faludi
authors.affiliation: Fresenius Medical Care, Semmelweis University, Budapest, Hungary.
authors.forename: Klára
authors.initials: K
authors.lastname: Berta
authors.affiliation: Department of Mathematics, Louisiana State University Shreveport, Shreveport, LA, USA.
authors.forename: Tibor
authors.initials: T
authors.lastname: Szarvas
authors.affiliation: Department of Mathematics, Louisiana State University Shreveport, Shreveport, LA, USA.
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Lengvárszky
authors.affiliation: Division of Nephrology, Department of Medicine, University of Tennessee Health Science Center, Memphis, TN, USA.
authors.forename: Miklos Z
authors.initials: MZ
authors.lastname: Molnar
authors.affiliation: Medical Service, Overton Brooks Veterans' Administration Medical Center, Shreveport, LA, USA.|Department of Internal Medicine, Louisiana State University Health School of Medicine, Shreveport, LA, USA.
authors.forename: Neville R
authors.initials: NR
authors.lastname: Dossabhoy
authors.affiliation: Division of Nephrology, Department of Medicine, University of Mississippi Medical Center, 2500 North State Street, L 504, Jackson, MS, 39216-4505, USA. tiborfulop.nephro@gmail.com.
authors.forename: Tibor
authors.initials: T
authors.lastname: Fülöp
mesh_terms: D000368:Aged; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006813:Humidity; D007676:Kidney Failure, Chronic / Q000175:diagnosis / Q000628:therapy*; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D006435:Renal Dialysis / Q000009:adverse effects* / Q000379:methods; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013696:Temperature; D015430:Weight Gain
keywords: Compliance; Fluid overload; Humidity; Residual urine output; Sweating; Temperature