title: Results of the Controlled ONset Verapamil INvestigation of Cardiovascular Endpoints (CONVINCE) trial by geographical region.
abstract: OBJECTIVE
  To examine regional differences in the Controlled ONset Verapamil INvestigation of Cardiovascular Endpoints (CONVINCE) trial.
  
  
  METHODS
  Double-blind, randomized, international clinical trial.
  
  
  METHODS
  Six hundred and sixty-one clinical centers in 15 countries.
  
  
  METHODS
  Hypertensive volunteers (n = 16,602) with > or =1 additional cardiovascular risk factor, grouped into four regions: USA (n = 8144), Canada (n = 3405), Western Europe (Spain, UK, Italy, Sweden, Germany; n = 2048) or 'other' (Bulgaria, Israel, Mexico, Czech Republic, Hungary, Poland, Slovakia, Brazil; n = 2879); subgroupings included country and state/province within the USA and Canada.
  
  
  METHODS
  Randomized to COER-verapamil or the investigator's choice of either atenolol or hydrochlorothiazide, titrated and additional drugs added as required.
  
  
  METHODS
  Baseline characteristics; blood pressure control, medication adherence and lost-to-follow-up at 2 years; and composite primary endpoint (stroke, myocardial infarction, cardiovascular death) by regional groupings.
  
  
  RESULTS
  Regional differences were found at baseline for age, gender, blood pressure, percentage receiving antihypertensive drug therapy, initial choice of atenolol or hydrochlorothiazide, and risk factor profile. Blood pressure control rates increased markedly during follow-up in all regions, but varied significantly by region. Blood pressure control, medication adherence and lost-to-follow-up rates were poorest in the USA. After adjustment for baseline differences, the primary-event rate for each region was significantly lower than for the USA. Although baseline factors, blood pressure control and event rates varied by region, treatment differences did not.
  
  
  CONCLUSIONS
  Despite differences in baseline and follow-up measures across geographical regions, the absence of treatment differences by region suggests that the overall findings of CONVINCE are robust.
authors.affiliation: Department of Preventive Medicine, Rush University Medical Center, Chicago, Illinois 60612, USA. hblack@rush.edu
authors.forename: Henry R
authors.initials: HR
authors.lastname: Black
authors.forename: William J
authors.initials: WJ
authors.lastname: Elliott
authors.forename: Gregory
authors.initials: G
authors.lastname: Grandits
authors.forename: Patricia
authors.initials: P
authors.lastname: Grambsch
authors.forename: Tracy
authors.initials: T
authors.lastname: Lucente
authors.forename: James D
authors.initials: JD
authors.lastname: Neaton
authors.forename: Richard H
authors.initials: RH
authors.lastname: Grimm
authors.forename: Lennart
authors.initials: L
authors.lastname: Hansson
authors.forename: Yves
authors.initials: Y
authors.lastname: Lacourcière
authors.forename: James E
authors.initials: JE
authors.lastname: Muller
authors.forename: Peter
authors.initials: P
authors.lastname: Sleight
authors.forename: Michael A
authors.initials: MA
authors.lastname: Weber
authors.forename: William B
authors.initials: WB
authors.lastname: White
authors.forename: Gordon H
authors.initials: GH
authors.lastname: Williams
authors.forename: Janet
authors.initials: J
authors.lastname: Wittes
authors.forename: Alberto
authors.initials: A
authors.lastname: Zanchetti
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Anders
mesh_terms: D000368:Aged; D001794:Blood Pressure / Q000187:drug effects; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010349:Patient Compliance; D014700:Verapamil / Q000627:therapeutic use*
chemical_list: D014700:Verapamil