How to select lipid-lowering drugs and combination therapy strategies for dyslipidemia

How to Choose Lipid-Lowering Medications?

When lifestyle interventions fail to lower blood lipid levels above target values, medication should be considered. Because LDL-C has a proven atherosclerotic effect, in most cases, treatment for dyslipidemia should aim to lower LDL-C. Statins have a proven effect in lowering LDL-C and reducing cardiac events, with ample evidence-based medicine support. Therefore, statins are often the first-line treatment for lipid-lowering therapy.

For patients with high LDL-C and high TG levels, achieving target LDL-C levels is the primary treatment goal. After achieving target LDL-C levels, treatment measures should be selected based on TG levels.

Generally, in patients with mixed dyslipidemia, if TG levels are higher than 2.3 mmol/L (200 mg/dL) but lower than 4.5 mmol/L (400 mg/dL), initial use of statins can reduce TG levels by approximately 30%. If LDL-C has already reached its target level, and the patient's serum TG level is higher than 2.3 mmol/L (200 mg/dL) but lower than 3.4 mmol/L (300 mg/dL), the patient can be encouraged to actively control their diet, increase physical activity, and lose weight, or increase the statin dosage to further lower LDL-C levels and achieve target non-HDL-C levels.

However, if TG levels are >5.7 mmol/L (500 mg/dL), it is usually necessary to carefully add niacin or fibrate to lower TG as quickly as possible to prevent acute pancreatitis.

For patients with high LDL-C and significantly low HDL-C, LDL-C remains the primary target. After LDL-C is achieved, treatment is then based on HDL-C levels, primarily involving lifestyle interventions. If necessary, fibrates or niacin, which can increase HDL-C, may be used in combination, especially in cases of metabolic syndrome.

How to combine lipid-lowering drugs?

(1) Combination of statins and ezetimibe: These two drugs affect cholesterol synthesis and absorption respectively, producing a good synergistic effect. Combination therapy can reduce serum LDL-C by approximately 18% on top of statin therapy without increasing the adverse reactions of statins. Multiple clinical trials have observed that ezetimibe combined with different types of statins has a good lipid-lowering effect. Studies have shown that combining statins with ezetimibe in patients at very high risk of ASCVD and CKD can reduce cardiovascular events. For patients whose cholesterol levels are not controlled or who are intolerant to moderate-intensity statin therapy, combination therapy with moderate- or low-intensity statins and ezetimibe may be considered.

(2) Combination of statins and fibrates: The combination of these two drugs can more effectively lower LDL-C and TG levels and raise HDL-C levels, while lowering sLDL-C. Fibrates include fenofibrate, gemfibrozil, and bezafibrate, with fenofibrate having the most extensive research and the strongest evidence. Previous studies suggest that the combination of statins and fenofibrate can provide cardiovascular benefits to patients with high TG and low HDL-C levels. Fenofibrate is suitable for patients with severe hypertriglyceridemia with or without low HDL-C levels, especially those with diabetes and metabolic syndrome accompanied by dyslipidemia, and high-risk cardiovascular disease patients whose TG or HDL-C levels remain poorly controlled after statin therapy. Because statins and fibrates have similar metabolic pathways, both have the potential to damage liver function and carry the risk of myositis and myopathy. The chance of adverse reactions increases when used together. Therefore, the safety of combined use of statins and fibrates should be given high priority. The risk of myopathy is relatively higher when gemfibrozil is used in combination with statins. It is advisable to start with a small dose, taking fibrates in the morning and statins in the evening to avoid a significant increase in blood drug concentration, and to closely monitor muscle enzymes and liver enzymes. If no adverse reactions occur, the dose of statins can be gradually increased.

(3) Combined use of statins and n-3 fatty acids: The combined use of statins and fish oil preparations containing n-3 fatty acids can be used to treat mixed hyperlipidemia without increasing the adverse reactions of either drug. However, because taking larger doses of n-3 polyunsaturated fatty acids increases the risk of bleeding and increases calorie intake in diabetic and obese patients, long-term use is not recommended. Whether this combination can reduce cardiovascular events is still under investigation.