Results of the Controlled ONset Verapamil INvestigation of Cardiovascular Endpoints (CONVINCE) trial by geographical region.
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.
Black
Henry R
HR
Department of Preventive Medicine, Rush University Medical Center, Chicago, Illinois 60612, USA. hblack@rush.edu
Elliott
William J
WJ
Grandits
Gregory
G
Grambsch
Patricia
P
Lucente
Tracy
T
Neaton
James D
JD
Grimm
Richard H
RH
Hansson
Lennart
L
Lacourcière
Yves
Y
Muller
James E
JE
Sleight
Peter
P
Weber
Michael A
MA
White
William B
WB
Williams
Gordon H
GH
Wittes
Janet
J
Zanchetti
Alberto
A
Anders
Robert J
RJ
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*
D014700:Verapamil