The prevalence of dyslipidemia is significantly higher in type 2 diabetic patients than in non-diabetic patients and is an important risk factor for the increased incidence of cardiovascular complications in type 2 diabetic patients. Studies have concluded that dyslipidemia is the primary risk factor for fatal and non-fatal myocardial infarction in diabetic patients. According to the survey, 78.51% of type 2 diabetic patients in China have dyslipidemia, the patient awareness rate is only 55.5%, the overall treatment rate of dyslipidemia is only 44.8%, and the overall compliance rate of treated patients is only 11.6%. Therefore, early detection of dyslipidemia in type 2 diabetes and early intervention can prevent and treat atherosclerosis, reduce cardiovascular and cerebrovascular events and mortality, and its therapeutic significance is comparable to that of blood glucose control.
I. Characteristics of dyslipidemia in type 2 diabetic patients
The main causes of dyslipidemia in type 2 diabetic patients are excessive production and defective clearance of very low density lipoprotein (VLDL) and triglycerides (TG) due to insulin deficiency and insulin resistance. The characteristic lipid profile includes: elevated fasting and postprandial triglyceride levels, often with postprandial hypertriglyceridemia even after normal control of fasting glucose and triglyceride levels; normal or mildly elevated high-density lipoprotein cholesterol (HDL-C); and elevated levels of triglyceride-rich apolipoproteins.
Timing of lipid testing in type 2 diabetic patients
Patients with type 2 diabetes should have their lipid, lipoprotein and apolipoprotein levels tested at the same time as the diagnosis. If the patient has a normal lipid profile and multiple cardiovascular risk factors (male ≥45 years old or female ≥55 years old, smoking, obesity and family history of early-onset ischemic cardiovascular disease, etc.), the lipid profile should be tested every 3 months after the diagnosis of diabetes.
In patients with type 2 diabetes mellitus with abnormal lipid profile, if only lifestyle interventions are given, it is recommended to test lipid levels after 6-8 weeks to decide whether treatment regimen needs to be adjusted; if lipid-regulating drugs are given, lipid levels should be tested after the initial intervention week, and if they still do not reach the standard, the treatment regimen should be adjusted and reviewed after another 4 weeks; in diabetic patients with controlled lipid levels [LDL-C < 2.6 mmol/l, HDL-C>1.25mmol/l, it is recommended to test the blood glucose profile every six months.
III. Assessment of cardiovascular risk in type 2 diabetes mellitus
The need to start lipid-regulating drugs or the intensity of intervention in patients with type 2 diabetes depends on the level of their lipids, the severity of the risk factors they have.
1. High-risk groups: (1) Those without cardiovascular disease but aged >40 years and with more than 1 cardiovascular risk factor [hypertension, smoking, obesity, microalbuminuria, family history of early-onset ischemic cardiovascular disease, age (men ≥45 years, women ≥55 years), postmenopausal women, etc.]. (2) No cardiovascular disease, age <40 years, but LDL-C ≥2.6 mmol/l or combined with multiple risk factors.
2. Very high risk group: Patients with diabetes combined with cardiovascular disease, diabetes combined with carotid plaque or stenosis, diabetes combined with peripheral artery disease, regardless of their baseline LDL-C levels belong to very high risk group.
Strategies and targets of lipid-regulating therapy in type 2 diabetic patients
1. Lipid intervention in type 2 diabetic patients should be based on therapeutic lifestyle changes. Therapeutic lifestyle changes include dietary modification (reducing the intake of saturated fatty acids and cholesterol, controlling the intake of carbohydrates), weight reduction, increasing exercise, quitting smoking, limiting alcohol, limiting salt, etc.
2.The primary goal of lipid-regulating therapy in patients with type 2 diabetes is to reduce LDL.
(1) High-risk patients: Statin lipid regulators are preferred to achieve LDL-C target <2.6 mmmol/l;
(2) Very high-risk patients: statin lipid-modifying agents are immediately selected to make LDL-C targets regardless of baseline LDL-C levels. If the above therapeutic target is not achieved even after treatment with the maximum dose of statin lipid regulators, it is recommended to reduce LDL-C by 30%-40% from baseline or to combine with other lipid regulators such as cholesterol absorption inhibitors.
3. Other treatment goals.
(1) Hypertriglyceridemia: the treatment goal is TG<1.7mmol/l, emphasizing strict glycemic control first, after glycemic control, triglycerides can return to normal in some patients. tG in 1.70-, therapeutic lifestyle intervention should be performed first; tG in 2.26-4.5 mmol/l, therapeutic lifestyle intervention should be started at the same time with betablockers; tg>4.5 mmol/l, rapid reduction of TG level should be considered first with betablocker to prevent the occurrence of acute pancreatitis.
(2) Low HDL: If accompanied by high LDL-C, the primary goal remains to reduce LDL-C; the therapeutic goals for HDL are: >1.04 mmol/l in men and in women, either through therapeutic lifestyle interventions or the use of betablockers.
(3) Mixed hyperlipidemia (high LDL-C and high TG): emphasis on first strict glycemic control and intensive therapeutic lifestyle interventions. The primary goal is still to reduce LDL-C, statin lipid-lowering drugs can be preferred; if LDL-C has reached the standard, TG is still ≥2.3mmol/l change to fibrates or combined with statins. If TG>4.5 mmol/l, betablockers are preferred to lower triglycerides, and if TG<4.5 mmol/l, LDL-C level should be reduced.
V. Notes on lipid-regulating therapy for patients with type 2 diabetes
1.Regulate the medication.
In order to improve the rate of lipid regulating treatment in type 2 diabetic patients, we should ensure the safety of medication and advocate the standardized use of lipid regulating drugs.
2, lipid regulating drug dose and efficacy.
It is not advisable to increase the dose of drugs excessively for the unilateral pursuit of lower LDL-C target values, and statins can be used in combination with other lipid regulating drugs when necessary.
3. Combined medication
Mixed hyperlipidemia is common in type 2 diabetic patients. In order to improve the target rate of lipid regulating therapy, it is necessary to combine different types of lipid regulating drugs.
(1) Combination of statins and fibrates: If the mixed hyperlipidemia does not reach the standard with statins or fibrates alone, the combination of the two drugs can be considered. However, unless the mixed dyslipidemia is particularly serious, generally monotherapy should be used; if necessary, the combination should be cautious, but the dose should be small; the two drugs should be applied at separate times; when statins and fibrates are used in combination, fenofibrate is preferred; the combination should be used cautiously in old age, severe liver and kidney disease, and hypothyroidism, and the drug should be stopped promptly once abnormalities occur.
(2) Statins and ezetimibe combination: The available evidence shows that the combination of ezetimibe and low-dose statins can improve the dyslipidemia better than increasing the statin dose alone, and the safety is good.
4.Long-term maintenance treatment
Patients with diabetic dyslipidemia still need long-term maintenance therapy after their lipids reach the standard. After the occurrence of acute coronary syndrome in diabetic patients, intensive statin treatment should be adhered to for at least 2 years.
5. Strengthen health education and management of patients with dyslipidemia spectrum.
VI. Prevention and treatment strategies for dyslipidemia
Therapeutic lifestyle change is not only the basis for treating dyslipidemia in type 2 diabetic patients, but also a fundamental means to prevent dyslipidemia in type 2 diabetic patients. Therefore, patients should be educated to adjust their dietary structure and promote a healthy lifestyle. Adjusting the diet structure includes controlling total calories, reducing the intake of saturated fatty acids, increasing the intake of unsaturated fatty acids, controlling the intake of cholesterol, and increasing foods rich in vitamins and fiber. A healthy lifestyle includes weight loss, smoking cessation, alcohol control, salt restriction, aerobic exercise, and an optimistic and open-minded attitude toward life. All of these can effectively prevent dyslipidemia in patients with type 2 diabetes.