Association of temporal trends in risk factors and treatment uptake with coronary heart disease mortality, 1994-2005.
BACKGROUND
Coronary heart disease (CHD) mortality has declined substantially in Canada since 1994.


OBJECTIVE
To determine what proportion of this decline was associated with temporal trends in CHD risk factors and advancements in medical treatments.


METHODS
Prospective analytic study of the Ontario, Canada, population aged 25 to 84 years between 1994 and 2005, using an updated version of the validated IMPACT model, which integrates data on population size, CHD mortality, risk factors, and treatment uptake changes. Relative risks and regression coefficients from the published literature quantified the relationship between CHD mortality and (1) evidence-based therapies in 8 distinct CHD subpopulations (acute myocardial infarction [AMI], acute coronary syndromes, secondary prevention post-AMI, chronic coronary artery disease, heart failure in the hospital vs in the community, and primary prevention for hyperlipidemia or hypertension) and (2) population trends in 6 risk factors (smoking, diabetes mellitus, systolic blood pressure, plasma cholesterol level, exercise, and obesity).


METHODS
The number of deaths prevented or delayed in 2005; secondary outcome measures were improvements in medical treatments and trends in risk factors.


RESULTS
Between 1994 and 2005, the age-adjusted CHD mortality rate in Ontario decreased by 35% from 191 to 125 deaths per 100,000 inhabitants, translating to an estimated 7585 fewer CHD deaths in 2005. Improvements in medical and surgical treatments were associated with 43% (range, 11% to 124%) of the total mortality decrease, most notably in AMI (8%; range, -5% to 40%), chronic stable coronary artery disease (17%; range, 7% to 35%), and heart failure occurring while in the community (10%; range, 6% to 31%). Trends in risk factors accounted for 3660 fewer CHD deaths prevented or delayed (48% of total; range, 28% to 64%), specifically, reductions in total cholesterol (23%; range, 10% to 33%) and systolic blood pressure (20%; range, 13% to 26%). Increasing diabetes prevalence and body mass index had an inverse relationship associated with higher CHD mortality of 6% (range, 4% to 8%) and 2% (range, 1% to 4%), respectively.


CONCLUSIONS
Between 1994 and 2005, there was a decrease in CHD mortality rates in Ontario that was associated primarily with trends in risk factors and improvements in medical treatments, each explaining about half of the decrease.
Wijeysundera
Harindra C
HC
Division of Cardiology, Schulich Heart Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada. wijeysundera@gmail.com
Machado
Márcio
M
Farahati
Farah
F
Wang
Xuesong
X
Witteman
William
W
van der Velde
Gabrielle
G
Tu
Jack V
JV
Lee
Douglas S
DS
Goodman
Shaun G
SG
Petrella
Robert
R
O'Flaherty
Martin
M
Krahn
Murray
M
Capewell
Simon
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D002784:Cholesterol / Q000097:blood; D003327:Coronary Disease / Q000401:mortality* / Q000628:therapy*; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008962:Models, Theoretical; D009026:Mortality / Q000639:trends; D009864:Ontario / Q000453:epidemiology; D011446:Prospective Studies; D012307:Risk Factors
D002784:Cholesterol