title: Definition of ambulatory blood pressure targets for diagnosis and treatment of hypertension in relation to clinic blood pressure: prospective cohort study.
abstract: BACKGROUND
  Twenty-four hour ambulatory blood pressure thresholds have been defined for the diagnosis of mild hypertension but not for its treatment or for other blood pressure thresholds used in the diagnosis of moderate to severe hypertension. We aimed to derive age and sex related ambulatory blood pressure equivalents to clinic blood pressure thresholds for diagnosis and treatment of hypertension.
  
  
  METHODS
  We collated 24 hour ambulatory blood pressure data, recorded with validated devices, from 11 centres across six Australian states (n=8575). We used least product regression to assess the relation between these measurements and clinic blood pressure measured by trained staff and in a smaller cohort by doctors (n=1693).
  
  
  RESULTS
  Mean age of participants was 56 years (SD 15) with mean body mass index 28.9 (5.5) and mean clinic systolic/diastolic blood pressure 142/82 mm Hg (19/12); 4626 (54%) were women. Average clinic measurements by trained staff were 6/3 mm Hg higher than daytime ambulatory blood pressure and 10/5 mm Hg higher than 24 hour blood pressure, but 9/7 mm Hg lower than clinic values measured by doctors. Daytime ambulatory equivalents derived from trained staff clinic measurements were 4/3 mm Hg less than the 140/90 mm Hg clinic threshold (lower limit of grade 1 hypertension), 2/2 mm Hg less than the 130/80 mm Hg threshold (target upper limit for patients with associated conditions), and 1/1 mm Hg less than the 125/75 mm Hg threshold. Equivalents were 1/2 mm Hg lower for women and 3/1 mm Hg lower in older people compared with the combined group.
  
  
  CONCLUSIONS
  Our study provides daytime ambulatory blood pressure thresholds that are slightly lower than equivalent clinic values. Clinic blood pressure measurements taken by doctors were considerably higher than those taken by trained staff and therefore gave inappropriate estimates of ambulatory thresholds. These results provide a framework for the diagnosis and management of hypertension using ambulatory blood pressure values.
authors.affiliation: Baker IDI Heart and Diabetes Institute, Melbourne, Victoria 8008, Australia. geoff.head@baker.edu.au
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Head
authors.forename: Anastasia S
authors.initials: AS
authors.lastname: Mihailidou
authors.forename: Karen A
authors.initials: KA
authors.lastname: Duggan
authors.forename: Lawrence J
authors.initials: LJ
authors.lastname: Beilin
authors.forename: Narelle
authors.initials: N
authors.lastname: Berry
authors.forename: Mark A
authors.initials: MA
authors.lastname: Brown
authors.forename: Alex J
authors.initials: AJ
authors.lastname: Bune
authors.forename: Diane
authors.initials: D
authors.lastname: Cowley
authors.forename: John P
authors.initials: JP
authors.lastname: Chalmers
authors.forename: Peter R C
authors.initials: PR
authors.lastname: Howe
authors.forename: Jonathan
authors.initials: J
authors.lastname: Hodgson
authors.forename: John
authors.initials: J
authors.lastname: Ludbrook
authors.forename: Arduino A
authors.initials: AA
authors.lastname: Mangoni
authors.forename: Barry P
authors.initials: BP
authors.lastname: McGrath
authors.forename: Mark R
authors.initials: MR
authors.lastname: Nelson
authors.forename: James E
authors.initials: JE
authors.lastname: Sharman
authors.forename: Michael
authors.initials: M
authors.lastname: Stowasser
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure / Q000502:physiology; D001795:Blood Pressure Determination / Q000592:standards*; D018660:Blood Pressure Monitoring, Ambulatory / Q000592:standards; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D006973:Hypertension / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D011187:Posture; D012016:Reference Values; D055815:Young Adult
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