GPs urged to request HDL-cholesterol test to assess CHD risk
Measuring HDL-cholesterol is essential for accurately assessing a patient's coronary heart disease risk, according to a new study showing more than 40 per cent of high-risk
patients are missed by only
using total cholesterol levels.
The Joint British Societies risk prediction charts, based on the Framingham equation at the back of the BNF, suggest GPs use an approximation of 1mmol/l if they know a
patient's total cholesterol.
The study researchers tested the accuracy of this method by calculating 10-year CHD risks for 5,000 healthy men and women, first, by using measured HDL-cholesterol levels and, then, using the recommended estimate of 1mmol/l.
The results, due to be published in Journal of Cardiovascular Risk (April), showed measuring HDL-cholesterol provided accurate risk classification in 97 per cent of cases.
But when the figure was estimated, 42 per cent of people considered at 'highest risk' those with a greater than 30 per cent risk over 10 years were misclassified to a lower risk category.
Some 26 per cent of patients with a risk of 15 per cent or greater over 10 years were misclassified either as being at a lower or higher risk.
Study co-author Dr John Robson, senior lecturer in general practice at Queen Mary University London, said: 'I don't think most GPs are checking HDL-cholesterol.' Dr Robson, a GP in east London, added: 'In patients they think could be at CHD risk, GPs should always request a test.'
Fellow author Dr Sarah Wilson, research fellow in clinical pharmacology at the university, said the study showed a 'major problem' with approximating HDL-cholesterol.
She said: 'These individuals may be falsely reassured and denied further investigation and treatment to reduce their risk of coronary disease.
'Individuals at low risk may be considered for drug therapies, increasing their exposure to potentially serious adverse events, while those at higher risk may be denied effective treatments to reduce their risk.'
Professor Francesco Cappuccio, professor of primary care research and development at St George's Hospital Medical School in London, said: 'If you just approximate the HDL-cholesterol to 1mmol/l you are going to misjudge the level of risk, so basically you would not treat people at higher risk.'