title: Office blood pressure and 24-hour ambulatory blood pressure measurements: high proportion of disagreement in resistant hypertension.
abstract: OBJECTIVE
  To evaluate the accuracy and quantify the agreement between office blood pressure (BP) and daytime ambulatory BP monitoring in the assessment of BP control of patients with a clinical diagnosis of resistant hypertension.
  
  
  METHODS
  Office BP measurements were done in a cohort of 228 true resistant (TR) or white-coat resistant (WCR) hypertensives classified by ambulatory BP in a hypertension clinic in Rio de Janeiro in this validity study. The agreement between the daytime ambulatory BP and office BP was analyzed using the graphic methods of Altman -- Bland and survival -- agreement plots.
  
  
  RESULTS
  The likelihood ratio of a positive test result of office BP was 1.99 for the assessment of uncontrolled BP in TR patients and 1.05 for the WCR hypertensive patients. The Altman and Bland plot showed a significant difference between the two methods, and the presence of a fixed and a proportional bias. The survival-agreement plot showed that a tolerance limit of 20 mm Hg of difference between systolic office BP and systolic daytime ambulatory BP would generate a proportion of disagreement equal to 57.5%.
  
  
  CONCLUSIONS
  The office BP is still an important tool to monitor BP control of patients with TR hypertension, whereas the monitoring of patients with WCR hypertension requires ambulatory BP.
authors.affiliation: Institute of Community Health (IESC), Federal University of Rio de Janeiro, Brazil.
authors.forename: Cláudia Soares
authors.initials: CS
authors.lastname: Rodrigues
authors.forename: Katia Vergetti
authors.initials: KV
authors.lastname: Bloch
authors.forename: Armando
authors.initials: A
authors.lastname: da Rocha Nogueira
mesh_terms: D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects; D001795:Blood Pressure Determination / Q000379:methods*; D018660:Blood Pressure Monitoring, Ambulatory; D004351:Drug Resistance; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D006973:Hypertension / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D008297:Male; D008875:Middle Aged
chemical_list: D000959:Antihypertensive Agents