title: Seasonal variations of chronic hemodialysis dose in South Croatia.
abstract: BACKGROUND
  The dialysis parameters are used for prescribing the dose of dialysis therapy. Delivered dialysis dose could be calculated from predialysis and postdialysis blood urea concentrations. Seasonal variations in some clinical and laboratory variables occur among chronic hemodialysis patients. Seasonal variations in chronic hemodialysis dose have not been investigated. We prospectively compared hemodialysis adequacy parameters in order to demonstrate its seasonal differences.
  
  
  METHODS
  Data were processed on 201 single dialysis treatments involving a group of 51 anuric chronic hemodialysis patients. The study period was 12 months. Four measurements per subject were obtained (in January, April, July, and October).
  
  
  RESULTS
  We could not demonstrate seasonal variability in prescribed and delivered hemodialysis dose, in "delta" values (absolute differences between prescribed and delivered dialysis doses for the same hemodialysis treatment), or in ultrafiltration per hemodialysis. Seasonal differences were found in blood urea concentrations before and after hemodialysis (p = 0.001, p = 0.010). When the data were grouped into two groups: cold (January and October) and mild (April and July) months; we could not demonstrate significant differences in dialysis adequacy parameters, but there were differences in blood urea concentration before hemodialysis (26.06 +/- 14.73 vs. 24.35 +/- 4.50, p = 0.004), blood urea concentration alter hemodialysis (10.24 +/- 2.96 vs. 9.43 +/- 2.60, p = 0.019), and ultrafiltration per hemodialysis (3.36 +/- 1.13 vs. 3.10 +/- 1.11, p = 0.046).
  
  
  CONCLUSIONS
  Based of the results of this investigation conducted on chronically hemodialyzed patients in the mild Mediterranean climate in South Croatia, Europe; we have concluded that clinicians should not pay attention to season when they prescribe hemodialysis dose or analyze delivered hemodialysis dose.
authors.affiliation: Department of Hemodialysis, Medical Center Trogir, Trogir, Croatia. vedkovac@inet.hr
authors.forename: V
authors.initials: V
authors.lastname: Kovacic
authors.forename: L
authors.initials: L
authors.lastname: Roguljic
authors.forename: V
authors.initials: V
authors.lastname: Kovacic
mesh_terms: D001002:Anuria / Q000378:metabolism* / Q000628:therapy*; D001639:Bicarbonates / Q000008:administration & dosage*; D001806:Blood Urea Nitrogen; D015992:Body Mass Index; D002021:Buffers; D002118:Calcium / Q000008:administration & dosage; D002908:Chronic Disease; D002980:Climate; D017523:Croatia; D005260:Female; D015312:Hemodialysis Solutions / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D011188:Potassium / Q000008:administration & dosage; D011446:Prospective Studies; D006435:Renal Dialysis; D012621:Seasons; D012964:Sodium / Q000008:administration & dosage; D016896:Treatment Outcome
chemical_list: D001639:Bicarbonates; D002021:Buffers; D015312:Hemodialysis Solutions; D012964:Sodium; D011188:Potassium; D002118:Calcium