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Predicting coronary risk in the general population--is it necessary to measure high-density lipoprotein cholesterol?
Sarah Wilson1, Atholl Johnston, John Robson
1Clinical Pharmacology, William Harvey Research Institute, Barts and The London, Queen Mary's School of Medicine and Dentistry, Charterhouse Square, London EC1 M 6BQ, UK. s.l.wilson@qmul.ac.uk
Insights
Using an estimated high-density lipoprotein cholesterol value of 1 mmol/l significantly reduces the accuracy of coronary heart disease risk assessments. Measuring actual high-density lipoprotein cholesterol is crucial for reliable risk prediction.
Area of Science:
- Cardiology
- Preventive Medicine
- Public Health
Background:
- The Joint British Societies Coronary Risk Prediction Charts suggest using a high-density lipoprotein cholesterol (HDL-C) value of 1 mmol/l when actual measurements are unavailable.
- Accurate coronary risk assessment is vital for guiding effective treatment decisions.
Purpose of the Study:
- To quantify the impact of using an estimated HDL-C value of 1 mmol/l on coronary heart disease (CHD) risk prediction accuracy.
- To compare the performance of the Joint British Societies charts with measured versus estimated HDL-C values against the Framingham equation.
Main Methods:
- Calculated CHD risks for 5005 individuals from the Health Survey for England 1998 using Joint British Societies charts.
- Recalculated risks using an assumed HDL-C of 1 mmol/l and compared with Framingham equation-derived risks.
- Determined sensitivity, specificity, positive, and negative predictive values for both scenarios.
Main Results:
- At the 30% 10-year CHD risk threshold, charts with measured HDL-C showed 83% sensitivity and 99% specificity.
- Using an estimated HDL-C of 1 mmol/l decreased sensitivity to 58% while specificity remained high at 98%.
Conclusions:
- Good agreement exists between Framingham and Joint British Societies charts when measured HDL-C is used.
- A fixed HDL-C value of 1 mmol/l introduces significant errors in CHD risk assessment.
- Measuring both total and HDL-C is essential for accurate coronary risk evaluation.
Background:
The Joint British Societies Coronary Risk Prediction Charts recommend the use of a high-density lipoprotein cholesterol value of 1 mmol/l where actual values have not been measured. It is important to quantify the impact of this advice if risk assessments are to be sufficiently accurate to guide treatment decisions.
Design:
The risks of 5005 individuals from the Health Survey for England 1998 were calculated using the Joint British Societies charts. Each individual's risk was recalculated assuming a high-density lipoprotein cholesterol value of 1 mmol/l. These risk estimates were compared with those derived from the Framingham equation.
Methods:
Using the Framingham equation as the gold standard, the positive and negative predictive values, sensitivity and specificity with 95% confidence intervals of the Joint British charts with actual and estimated high-density lipoprotein cholesterol values were calculated.
Results:
At the 30% 10-year coronary heart disease risk threshold using measured high-density lipoprotein cholesterol values, the charts had a sensitivity of 83% and specificity of 99%. Using an estimated high-density lipoprotein cholesterol value of 1 mmol/l reduced the sensitivity to 58% with a specificity of 98%.
Conclusions:
In the presence of measured high-density lipoprotein cholesterol values there was good agreement between the Framingham equation and the Joint British Societies charts. The use of a fixed high-density lipoprotein cholesterol value of 1 mmol/l introduced important and significant errors into the risk assessment. This study reinforces the need to measure both total and high-density lipoprotein cholesterol when assessing coronary risk.