General practitioners' use of absolute risk versus individual risk factors in cardiovascular disease prevention: an experimental study.
OBJECTIVE
To understand general practitioners' (GPs) use of individual risk factors (blood pressure and cholesterol levels) versus absolute risk in cardiovascular disease (CVD) risk management decision-making.


METHODS
Randomised experiment. Absolute risk, systolic blood pressure (SBP), cholesterol ratio (total cholesterol/high-density lipoprotein (TC/HDL)) and age were systematically varied in hypothetical cases. High absolute risk was defined as 5-year risk of a cardiovascular event >15%, high blood pressure levels varied between SBP 147 and 179 mm Hg and high cholesterol (TC/HDL ratio) between 6.5 and 7.2 mmol/L.


METHODS
4 GP conferences in Australia.


METHODS
144 Australian GPs.


RESULTS
GPs indicated whether they would prescribe cholesterol and/or blood pressure lowering medication. Analyses involved logistic regression.


RESULTS
For patients with high blood pressure: 93% (95% CI 86% to 96%) of high absolute risk patients and 83% (95% CI 76% to 88%) of lower absolute risk patients were prescribed blood pressure medication. Conversely, 30% (95% CI 25% to 36%) of lower blood pressure patients were prescribed blood pressure medication if absolute risk was high and 4% (95% CI 3% to 5%) if lower. 69% of high cholesterol/high absolute risk patients were prescribed cholesterol medication (95% CI 61% to 77%) versus 34% of high cholesterol/lower absolute risk patients (95% CI 28% to 41%). 36% of patients with lower cholesterol (95% CI 30% to 43%) were prescribed cholesterol medication if absolute risk was high versus 10% if lower (95% CI 8% to 13%).


CONCLUSIONS
GPs' decision-making was more consistent with the management of individual risk factors than an absolute risk approach, especially when prescribing blood pressure medication. The results suggest medical treatment of lower risk patients (5-year risk of CVD event <15%) with mildly elevated blood pressure or cholesterol levels is likely to occur even when an absolute risk assessment is specifically provided. The results indicate a need for improving uptake of absolute risk guidelines and GP understanding of the rationale for using absolute risk.
Screening and Test Evaluation Program (STEP), School of Public Health, The University of Sydney, Sydney, New South Wales, Australia Centre for Medical Psychology & Evidence-based Decision-making (CeMPED), The University of Sydney, Sydney, New South Wales, Australia.
Jesse
J
Jansen
Screening and Test Evaluation Program (STEP), School of Public Health, The University of Sydney, Sydney, New South Wales, Australia Centre for Medical Psychology & Evidence-based Decision-making (CeMPED), The University of Sydney, Sydney, New South Wales, Australia.
Carissa
C
Bonner
Screening and Test Evaluation Program (STEP), School of Public Health, The University of Sydney, Sydney, New South Wales, Australia Centre for Medical Psychology & Evidence-based Decision-making (CeMPED), The University of Sydney, Sydney, New South Wales, Australia.
Shannon
S
McKinn
Screening and Test Evaluation Program (STEP), School of Public Health, The University of Sydney, Sydney, New South Wales, Australia.
Les
L
Irwig
Screening and Test Evaluation Program (STEP), School of Public Health, The University of Sydney, Sydney, New South Wales, Australia Centre for Research in Evidence Based Practice Faculty of Health Sciences and Medicine, Bond University, Robina, Queensland, Australia.
Paul
P
Glasziou
Screening and Test Evaluation Program (STEP), School of Public Health, The University of Sydney, Sydney, New South Wales, Australia Centre for Research in Evidence Based Practice Faculty of Health Sciences and Medicine, Bond University, Robina, Queensland, Australia.
Jenny
J
Doust
Screening and Test Evaluation Program (STEP), School of Public Health, The University of Sydney, Sydney, New South Wales, Australia.
Armando
A
Teixeira-Pinto
School of Public Health and Community Medicine, University of New South Wales, Sydney, New South Wales, Australia.
Andrew
A
Hayen
Screening and Test Evaluation Program (STEP), School of Public Health, The University of Sydney, Sydney, New South Wales, Australia.
Robin
R
Turner
Screening and Test Evaluation Program (STEP), School of Public Health, The University of Sydney, Sydney, New South Wales, Australia Centre for Medical Psychology & Evidence-based Decision-making (CeMPED), The University of Sydney, Sydney, New South Wales, Australia.
Kirsten
K
McCaffery
D001794:Blood Pressure; D002318:Cardiovascular Diseases / Q000097:blood / Q000517:prevention & control*; D002784:Cholesterol / Q000097:blood; D000066491:Clinical Decision-Making; D005260:Female; D058006:General Practice; D006801:Humans; D008297:Male; D008875:Middle Aged; D010818:Practice Patterns, Physicians'; D018570:Risk Assessment; D012307:Risk Factors; D012308:Risk Management
D002784:Cholesterol
Cardiology; General Medicine (see Internal Medicine); Public Health