Nothing has been met with more surprise and debate than the newest guideline on cholesterol treatment which was jointly issued by the American College of Cardiology (ACC) and American Heart Association (AHA) just about 2 weeks ago. The last guideline, named as the third report of the Adult Treatment

Panel (ATP-3), by the National Heart, Lung and Blood Institute (NHLBI) was already 12 years old and had not been updated since 2004. Since then, there had been many new findings from cholesterol researches and a new guideline seems long overdue. What surprised most people is that the new guideline totally abandons the concept of LDL-cholesterol and non-HDL-cholesterol treatment targets, which people are already so used to. Instead, it identifies 4 groups of patients in whom doctors should focus their efforts to achieve relative reductions in LDL cholesterol by giving the appropriate intensity of statin therapy in order to reduce cardiovascular events or complications. The aim of this change in the guideline is to maximize the benefit of statin therapy without overtreatment of patients. To those whose mind-set still remains in the old targets, the new guideline represents a whole new paradigm shift.

The 4 major patient groups who greatly benefit from statin treatment include: 1. Individuals with evidence of clinical atherosclerotic cardiovascular disease such as angina, myocardial infarction, stroke, peripheral vascular disease, undergone angioplasty or coronary bypass surgery etc; 2. Individuals with LDL-cholesterol levels equal or above 4.9 mmol/L; 3. Individuals with diabetes aged 40-75 years old with LDL-cholesterol levels between 1.8 and 4.8 mmol/L and without evidence of atherosclerotic cardiovascular disease; and 4. Individuals without evidence of cardiovascular disease or diabetes but who have LDL-cholesterol levels between 1.8 and 4.8 mmol/L and a 10-year risk of atherosclerotic cardiovascular disease equal or above 7.5% as calculated by the Pooled Cohort Equations, which was developed by the ACC/AHA Risk Assessment Work Group.

For groups 1 and 2, the guideline recommends to use high-intensity statin treatment to reduce the LDL-cholesterol levels by more than 50%. For groups 3 and 4, moderate-intensity statin treatment to reduce the LDL-cholesterol levels by 30% to 49% is recommended. If the risk profile of patients in groups 3 and 4 is particularly high, a high-intensity statin regime would be appropriate.

The guideline simplifies the algorithm of cholesterol treatment tremendously when compared with the old ones. What remains the most controversial part of the guideline is the risk assessment by the Pooled Cohort Equations, which some researchers throw doubts in its predictive accuracy while supporters believe it enables more susceptible individuals to benefit from the statin treatment. A 2013 Cochrane meta-analysis showed that statin use in primary prevention would reduce all-cause mortality, fatal and nonfatal cardiovascular disease, stroke and coronary revascularization by 14% to 38% without increase in risks of the drug adverse effects. So, it would seem that the new guideline would be beneficial to the population as a whole but in the expense of treating some lower risk individuals with statin. The guideline is by no means intended to provide a comprehensive approach to managing lipids and that many unanswered questions remain. At present, it represents the best evidence-based approach to deal with the cholesterol treatment issue until further new findings in the upcoming randomized trials become available to be incorporated into future guidelines.

Written by Dr. Fong Ping Ching