New study from the LIPID trial


Which lipid should we monitor?

26 February 2014

Many of us are familiar with the regular check by the GP of our cholesterol level - the blood sample and then the number indicating the state of our arteries and whether we need to get it down by diet and exercise. Cholesterol is one of the risk factors for diseases of the arteries, such as heart disease and stroke. 

Decisions about treatment should start with the absolute risk. A person with a medium or high risk should work on ways of reducing this risk. It can be tested out at www.cvdcheck.org.au. When the doctor has made a decision to investigate, how should he or she best monitor what is happening to cholesterol?

Researchers have used the data from the CTC's LIPID trial to answer this question. LIPID had over 9000 patients at risk of cardiovascular events who had regular blood tests for over 5 years. Half of them were taking a statin and half a placebo. This very large data set has been analysed to see which laboratory test would be best at predicting risk. The research group looked at total cholesterol, LDL and HDL cholesterols and their ratios, triglycerides, and apolipoproteins and their ratios.

They also examined how clearly and rapidly the measures would change in response to statin treatment.

For predicting a cardiovascular event, the LDL/HDL cholesterol ratio was the best indicator. Overall, for monitoring risk in people who have had a heart attack and are on a statin, the ratios of LDL/HDL cholesterol or the ratio of total/HDL cholesterol are both worthwhile. A cholesterol difference, the non-HDL cholesterol level, is also a good indicator and can be easily calculated.

Total cholesterol, the familiar number, was not the the best measure from any point of view.

The drug in this study was an older statin, pravastatin, which is not often prescribed now. Although the relationships between cholesterol changes and outcomes appear to be consistent across the statins, the study needs to be confirmed with the more modern drugs.

With over 2 million Australians taking statins and many more having their blood cholesterol checked regularly, the results of the study have widespread relevance in this country.

Glasziou PP, Irwig L, Kirby AC, Tonkin AM, Simes RJ. Which lipid measurement should we monitor? An analysis of the LIPID study. BMJ Open 2014; 4(2): e003512