title: Head-up tilt testing for detecting orthostatic hypotension: how long do we need to wait?
abstract: BACKGROUND
  Orthostatic hypotension (OH) is a common underdiagnosed condition characterized by a fall in systolic or diastolic blood pressure (BP). There is some uncertainty about the minimum duration needed to detect OH beyond 3 min (delayed OH). We aimed to define a minimum time range for measurement of delayed OH in subjects referred to as tilt testing.
  
  
  METHODS
  A repeated measurements study Tel-Aviv Medical Center, on 692 subjects who underwent prolonged (40 min, vertical position) drug-free tilt testing. Survival curves were used to study time to an OH event; logistic regression to study factors associated with delayed OH and mixed models to study the pattern of repeated BP measures.
  
  
  RESULTS
  In our sample, 17% had OH within 3 min, 35% within 30 min, and 40% within 40 min. Among the 270 OH patients, 43 and 91% were identified within 3 and 30 min, respectively. Delayed OH was associated with female gender (OR = 1.95, 1.16-3.27) and age <65 years (OR = 2.17, 1.24-3.80). Older patients differed significantly from younger patients in BP pattern changes and had a higher rate of a fall in systolic BP.
  
  
  CONCLUSIONS
  Tilt testing for 30 min identifies most cases of delayed OH in older patients, while those younger than 65 years need 10 min longer.
authors.affiliation: Movement Disorders Unit and Neuroautonomic service, Department of Neurology, Tel-Aviv Sourasky Medical Center, Tel-Aviv, Israel.
authors.forename: Tanya
authors.initials: T
authors.lastname: Gurevich
authors.forename: Hanadi
authors.initials: H
authors.lastname: Machmid
authors.forename: Dina
authors.initials: D
authors.lastname: Klepikov
authors.forename: Adi
authors.initials: A
authors.lastname: Ezra
authors.forename: Nir
authors.initials: N
authors.lastname: Giladi
authors.forename: Chava
authors.initials: C
authors.lastname: Peretz
mesh_terms: D000328:Adult; D000368:Aged; D001794:Blood Pressure / Q000502:physiology; D005260:Female; D006801:Humans; D007024:Hypotension, Orthostatic / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011187:Posture / Q000502:physiology; D018667:Tilt-Table Test; D013997:Time Factors; D055815:Young Adult