title: Effect of Dialysis Day on Intradialytic Hypotension Risk.
abstract: OBJECTIVE
  Intradialytic hypotension (IDH) is a serious and frequent complication of hemodialysis (HD). Thus far, data are scarcely available to assess the impact of first versus subsequent HD sessions of the week in IDH. Therefore, the purpose of this work was to evaluate IDH risk in patients on thrice-weekly HD.
  
  
  METHODS
  We conducted an analysis of all blood pressure (BP) measurements obtained during 492 HD treatments given to 41 prevalent adult patients over a one month period. A logistic regression model for repeated binary observations was used to determine the association between hypotension and patient and dialysis factors.
  
  
  RESULTS
  The incidence of IDH was 32.5%. First dialysis session of the week was associated with a 9% higher risk of hypotension relatively to the second one. The risk was even higher from the first to the third session of the week (60%) and from the second to the third (50%). A higher hypotension odds ratio was also associated with age (1.03, 90% CI: 1.01-1.06), higher predialysis BP (1.04, 90%CI: 1.03-1.05) and higher phosphorus level (1.38, 90% CI: 1.07-1.76). The risk decreased 24.4% for each additional antihypertensive drug taken by the patient.
  
  
  CONCLUSIONS
  The odds of hypotension occurrence decrease throughout dialysis sessions of the week. Minimizing modifiable risk factors may decrease IDH episodes.
authors.affiliation: Sx00E3;o Francisco Dialysis Unit, Porto, Portugal.
authors.forename: Ana
authors.initials: A
authors.lastname: Rocha
authors.forename: Clemente
authors.initials: C
authors.lastname: Sousa
authors.forename: Paulo
authors.initials: P
authors.lastname: Teles
authors.forename: Augusto
authors.initials: A
authors.lastname: Coelho
authors.forename: Eva
authors.initials: E
authors.lastname: Xavier
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007022:Hypotension / Q000175:diagnosis* / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D006435:Renal Dialysis / Q000009:adverse effects* / Q000379:methods*; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors