Overview
An umbrella term for a group of diseases centered on insulin resistance or obesity mainly manifested as obesity, hypertension, hyperglycemia or insulin resistance, dyslipidemia, etc. The occurrence and development of these diseases are related to genetic and environmental factors In principle, lifestyle treatment is initiated first, followed by pharmacological treatment for various risk factors
Definition
Metabolic syndrome is a collective term for a group of disorders in which obesity, hyperglycemia, dyslipidemia, and elevated blood pressure occur concurrently or sequentially, seriously affecting the health of the body.
The metabolic syndrome is a combination of metabolically interrelated risk factors that directly contribute to the development of atherosclerotic cardiovascular disease and increase the risk of developing type 2 diabetes.
Morbidity
With the improvement of living standards in China, the urbanization of the country, and the increasing prevalence of obesity and overweight, the prevalence of metabolic syndrome has been increasing year by year, generally showing a trend of higher prevalence in the north than in the south, and higher prevalence in urban than in rural areas.
The prevalence of metabolic syndrome in the Chinese adult population is 16.5%, i.e., about 16 to 17 per 100 people [1].
The prevalence of metabolic syndrome increases with age, and the prevalence of metabolic syndrome among the elderly in China is as high as 50%, i.e., one out of every two elderly people suffers from this disease [2].
Causes
Causes
The specific mechanism of metabolic syndrome has not been clarified, and its occurrence is the result of a complex interaction between genetic and environmental factors [3].
Genetic factors
Recent studies have identified a genetic predisposition to metabolic syndrome, and although no genes have been found to be individually associated with it, there is a familial clustering of the onset of metabolic syndrome in some cases.
Some studies have shown that the gene sequences of several lipid metabolism-related proteins, including apolipoprotein A5, are associated with the development of metabolic syndrome.
Environmental factors
Diet has a great influence on the development of metabolic syndrome. For example, long-term consumption of high-fat and high-sugar diets can lead to insulin resistance, dyslipidemia, digestive and absorption disorders, and impaired liver function, thus dramatically increasing the risk of developing metabolic syndrome.
In addition, poor lifestyle habits can also increase the incidence of metabolic syndrome, such as long-term smoking, alcohol consumption, sedentary patients are more likely to develop metabolic function abnormalities, the incidence of metabolic syndrome is also higher.
High risk factors
People with high risk factors are at higher risk of developing the disease, but they may not always develop the disease.
The main risk factors for metabolic syndrome are overweight or obesity, physical inactivity, smoking, excessive consumption of foods high in sugar or saturated fat, older age, menopause, and a family history of metabolic syndrome or diabetes mellitus [4].
Pathogenesis
The pathogenesis of metabolic syndrome has not been fully elucidated, and it is currently believed that the body’s reduced sensitivity to insulin, i.e. insulin resistance, is the center of metabolic syndrome, and obesity, especially central obesity, is closely related to the occurrence of insulin resistance.
On the one hand, insulin resistance is related to the occurrence mechanism of many diseases of metabolic syndrome, and on the other hand, the occurrence mechanism of insulin resistance is related to the pathological changes of obesity and metabolic syndrome, which are causal and have an intricate relationship with each other.
Symptoms
Main Symptoms
Metabolic syndrome is a complex group of syndromes, mainly manifested as obesity, hypertension, hyperglycemia or insulin resistance, dyslipidemia, etc. [5].
Obesity
Obesity, especially central obesity, is more closely related to the onset of the disease, which can be manifested as weight gain, increased waist circumference, and obvious accumulation of abdominal fat, while the limbs are not fat.
Hypertension
Early clinical symptoms of hypertension are not obvious, only headache, dizziness and other non-specific symptoms, mostly found in physical examination or treatment of other diseases with elevated blood pressure.
Hyperglycemia
Hyperglycemia may include impaired fasting glucose, abnormal glucose tolerance, and diabetes.
Patients may have no obvious symptoms, or may exhibit excessive drinking, excessive eating, excessive urination, unexplained weight loss, and numbness in the hands and feet.
Insulin Resistance
Typical patients may develop acanthosis nigricans, which is characterized by brown thickened skin in the armpits, groin, and back of the neck.
Dyslipidemia
Early on, there may be no obvious symptoms. Typical features include elevated triglycerides or lowered high-density lipoprotein.
Complications
Long-term complications of metabolic syndrome are mainly cardiovascular diseases.
Cardiovascular diseases
Including coronary heart disease, arrhythmia, heart failure, etc., there may be palpitations, shortness of breath, sitting breathing, nocturnal paroxysmal dyspnea, pressure or tightness pain behind the sternum, chest tightness and discomfort, edema, etc., which may lead to death in severe cases.
Cerebrovascular disease
Including cerebral infarction, cerebral hemorrhage, etc., which may be manifested as hemiparesis on one side of the limb, dysphagia, limb weakness, slurred speech, aphasia and coma.
Medical Treatment
Department of Medicine
Endocrinology
If you notice weight gain or weight loss, elevated blood glucose, dry mouth, excessive drinking, excessive eating, excessive urination, numbness of hands and feet, blurred vision, etc., it is recommended to consult the Department of Endocrinology in a timely manner.
Cardiovascular Medicine
If you find symptoms such as elevated blood lipids, dizziness, headache, palpitations, chest tightness, chest pain, etc., it is recommended to consult the Department of Cardiovascular Medicine in time.
Neurology
For symptoms such as hemiplegia, limb weakness, slurred speech, aphasia, coma, etc., it is recommended to consult the Department of Neurology in time.
Nutrition
If you are overweight or obese, please consult the Department of Nutrition for dietary guidance and weight control.
Preparation
Consultation: Registration, Preparation of documents, Frequently Asked Questions
Consultation Tips
If you have high blood glucose or high blood pressure, it is recommended to record the time and value of blood glucose and blood pressure measurements for the doctor’s reference.
Preparation Checklist
Symptom list
Pay special attention to the time of onset of symptoms, special manifestations, etc.
Is there any sudden weight gain or loss?
Is there any dizziness or headache?
Is there dry mouth, excessive drinking, eating or urinating?
Medical history list
Any previous history of diabetes mellitus, hypertension, hyperlipidemia, etc.?
Any past history of coronary heart disease, cerebral infarction, etc.?
Any family history of diabetes mellitus, hypertension, hyperlipidemia, etc.?
Checklist
Test results in the past six months, which can be brought to the doctor’s office
Laboratory tests: blood routine, urine routine, blood biochemistry, glycated hemoglobin, etc.
Imaging tests: abdominal ultrasound, echocardiography, etc.
Other tests: electrocardiogram, ambulatory blood pressure monitoring, etc.
Medication List
Medication used in the last 3 months, if there is a box or package of medication, you can bring it to the doctor’s appointment
Weight-lowering medication: Orlistat, etc.
Glucose-lowering drugs: metformin, acarbose, glimepiride, dagliflozin, pioglitazone, etc.
Antihypertensive drugs: Chlorosartan potassium, nifedipine extended-release tablets, metoprolol, captopril, etc.
Lipid-lowering drugs: fenofibrate, atorvastatin, ezetimibe, etc.
Diagnosis
Diagnosis is based on
Medical history
Patients with this disease may have a history of the following
Family history of diabetes mellitus, hypertension, hyperlipidemia, metabolic syndrome.
History of overweight or obesity, diabetes mellitus, hypertension, hyperlipidemia, coronary heart disease, and cerebral infarction.
Clinical manifestations
There may be manifestations of obesity, hyperglycemia, dyslipidemia, and elevated blood pressure, such as weight gain, thickening of waist circumference, polydipsia, polyphagia, polyuria, dizziness, and headache.
Laboratory Tests
Lipid Profile
By measuring total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides in the blood, the health status of the body is analyzed, the risk of cardiovascular disease is assessed, and the efficacy of treatment is evaluated.
Patients may have elevated total cholesterol, triglycerides, LDL cholesterol, and decreased HDL cholesterol.
Blood glucose measurement and oral glucose tolerance test
Elevated blood glucose is the main basis for the diagnosis of diabetes mellitus and the main indicator of the condition and control of diabetes mellitus.
The determination of oral glucose tolerance test (OGTT) needs to pay attention to the following matters.
Fasting for 8 to 10 hours before the test, and after 12:00 p.m. the night before the test.
Fasting blood is drawn first on the day of the test.
Dissolve 75 grams of glucose in 250 to 300 ml of warm boiled water and drink it within 5 minutes after it has melted.
Start timing from the first sip and measure the blood glucose after 2 hours, or take blood at half an hour, 1 hour, 2 hours and 3 hours to measure the blood glucose level.
No smoking, alcohol, coffee and tea, and no strenuous exercise during the test.
Glycated hemoglobin and glycated plasma albumin measurement
Glycated hemoglobin (HbA1c) reflects the average blood glucose level over the past 8 to 12 weeks.
Glycated plasma albumin reflects the average blood glucose level over 2 to 3 weeks.
Imaging
Echocardiography
To detect the structural and functional condition of the heart, with or without hypertrophy and enlargement of the left ventricle.
Ultrasound of the adrenal glands and renal arteries
Detects the structure and function of the kidneys and adrenal glands, and the renal arteries.
It can clarify or rule out secondary hypertension.
Ultrasound of the abdomen
Can help to identify the presence of fatty liver, this test needs to be done on an empty stomach.
Other Tests
Ambulatory Blood Pressure Monitoring
Measures blood pressure over a 24-hour period. It can identify changes in blood pressure and the relationship with time and daily behavior.
It can provide a basis for diagnosis and treatment planning.
Fundus examination
Examination of the blood vessels and retina of the fundus.
The damage to the fundus caused by high blood pressure and diabetes can be clarified.
Diagnostic Criteria
China’s diagnostic criteria for metabolic syndrome are as follows, with three or more can be diagnosed [6].
Abdominal obesity (i.e., central obesity): waist circumference ≥ 90 centimeters (cm) for men and ≥ 85 cm for women.
Hyperglycemia: fasting blood glucose ≥ 6.1 millimoles per liter (mmol/L) or 2-hour post-glycemic load blood glucose ≥ 7.8 mmol/L and/or those who have been diagnosed and treated for diabetes.
Hypertension: blood pressure ≥130/85 millimeters of mercury (mmHg) and/or confirmed and treated hypertension.
Fasting triglycerides ≥ 1.70 mmol/L.
Fasting HDL cholesterol <1.04 mmol/L.
Differential Diagnosis
The metabolic syndrome is a group of related clinical syndromes that focuses on differentiating the etiology of each clinical condition.
Obesity.
It is mainly differentiated from secondary obesity, i.e., obesity due to other diseases, such as Cushing’s syndrome, primary hypothyroidism, hypothalamic obesity, and polycystic ovary syndrome.
Hypertension
Mainly differentiated from secondary hypertension, such as Cushing’s syndrome, primary aldosteronism, obstructive sleep apnea, renal vascular disease, etc.
Hyperglycemia
Mainly differentiated from secondary hyperglycemia, such as Cushing’s syndrome, acromegaly, glucagonoma, etc.
Hyperlipidemia
Patients with dyslipidemia should be distinguished from hereditary dyslipidemia, such as familial hypertriglyceridemia and familial hypercholesterolemia.
Treatment
Aim of treatment: stop or delay its development into cardiovascular and cerebrovascular diseases and type 2 diabetes mellitus.
Treatment principle: Treatment can be initiated with lifestyle therapy followed by drug therapy for various risk factors.
General treatment
Mainly lifestyle intervention, including diet control and exercise.
Control of total dietary calorie intake: Adjust the dietary structure, reduce fat intake, and strictly control total dietary calorie intake.
Exercise exercise: for all sedentary obese patients, the current recommendation is to gradually increase aerobic exercise, such as brisk walking, in order to achieve the goal of 150 minutes or more per week [7].
Medication
Pharmacologic therapy focuses on reducing various risk factors. It includes reducing weight, controlling blood pressure, reducing insulin resistance and controlling blood glucose, and improving dyslipidemia.
Weight reduction
At present, the only drug approved for the treatment of obesity in China is orlistat, which can reduce fat absorption by inhibiting gastrointestinal pancreatic lipase.
Glucose-lowering drugs such as metformin and liraglutide are suggested to be used for obese or overweight diabetic patients.
Weight-loss pharmacotherapy is indicated for patients who have difficulty making lifestyle changes, have comorbid obesity-related conditions, and have had poor weight loss through exercise and dietary changes.
Control of blood pressure
Application of antihypertensive drugs: Angiotensin-converting enzyme inhibitors and angiotensin II receptor antagonists are recommended to be preferred, which can increase insulin sensitivity, such as captopril and chlorosartan potassium [8].
Hypotensive drugs are preferred to those that do not affect glucose and fat metabolism, so thiazide diuretics and beta-blockers are discouraged, but there is still controversy about the optimal antihypertensive treatment [9].
Reduction of insulin resistance and glycemic control
Among various hypoglycemic agents, metformin and thiazolidinediones (e.g., pioglitazone) are known to improve insulin resistance and increase insulin sensitivity.
Both metformin and alpha-glucosidase inhibitors (e.g., acarbose) slow the progression of prediabetes to type 2 diabetes.
Glucagon-like peptide-1 agonists, which suppress appetite and reduce energy intake, can be effective in lowering blood glucose and reducing body weight, as well as improving lipid profiles and lowering blood pressure, such as liraglutide.
Improvement of dyslipidemia
Common medications are Betaine and Statin.
Biotics: lower triglycerides, while mildly to moderately lowering cholesterol and LDL cholesterol, and raising HDL cholesterol, such as Fenofibrate, Benzafibrate, Gemfibrozil.
Statins: stronger cholesterol-lowering effect, mildly lower triglycerides and increase HDL cholesterol, such as: atorvastatin, resuvastatin, simvastatin, etc..
Surgery
Surgical procedures include laparoscopic gastric sleeve resection, laparoscopic Roux-en-Y gastric bypass and biliopancreatic diversion duodenal transposition.
Indications for surgery are seen in the following conditions and need to be decided by the surgeon based on the patient’s condition.
Patients with simple obesity when body mass index [BMI = weight (kg)/height (m2)] ≥37.5 kg/m2, aggressive surgery is recommended; 32.5 kg/m2 ≤ BMI <37.5 kg/m2, surgery is recommended [10].
Metabolic surgery is feasible in patients with type 2 diabetes when BMI ≥32.5 kg/m2; metabolic surgery may be chosen with caution when 27.5 kg/m2 ≤ BMI <32.5 kg/m2 and other cardiovascular risk factors are present [6].
Prognosis
Cure
Metabolic syndrome is a reversible disease and can be controlled if detected early and intervened early.
Prognostic factors
The prognosis of metabolic syndrome is related to whether early detection and early intervention, whether metabolic indexes such as blood glucose, blood pressure, blood lipids and so on reach the standard, whether combined with diabetes mellitus, cardiovascular and cerebral vascular diseases and so on.
Early detection and early intervention, active control of body weight and metabolic indexes such as blood glucose, blood pressure and blood lipids, and no combination of diabetes mellitus and cardio-cerebral vascular diseases are likely to have a good prognosis.
Late detection and intervention, poor control of body weight and metabolic indicators such as blood glucose, blood pressure and blood lipids, and the combination of diabetes mellitus and cardiovascular and cerebrovascular diseases are associated with a poorer prognosis, which may be life-threatening in severe cases.
Harmfulness
The danger of metabolic syndrome is mainly to increase the risk of diabetes and coronary heart disease and other cardiovascular diseases.
Daily
Daily management
Daily management of patients with metabolic syndrome mainly includes lifestyle management, diet management and exercise management.
Lifestyle management
Adopt good living habits, maintain a healthy state of mind, stop smoking, do not drink too much alcohol, and maintain a healthy weight.
Diet management
Low-fat diet, reduce the intake of sugar, salt, saturated fatty acid and processed food, fresh green leafy vegetables, low calorie fruits and whole grains are recommended.
Energy-restricted diet, low glycemic index diet, Mediterranean diet, etc. can be chosen under the advice of dietitians.
Energy-restricted diet: Reduce energy intake by 500~1,000 kcal per day (1,200~1,400kcal/d for men and 1,000~1,200kcal/d for women) on the basis of the target energy intake, or reduce the total energy by 1/3 compared with the recommended intake, among which, carbohydrates account for 55%~60% of the total energy per day, and fat accounts for 25%~30% of the total energy per day. 30%.
Low Glycemic Index Diet: A dietary structure based on low-glycemic foods. A food with a glycemic index <55 is generally considered to be a low glycemic index food.
Mediterranean Diet: Plant-based foods, including whole grains, legumes, vegetables, fruits, nuts, etc.; fish, poultry, eggs, dairy products in moderation, and red meat and its products in small amounts; edible oils, mainly olive oil; red wine in moderation. The fat energy ratio is 25% to 35%, with a low intake of saturated fatty acids (7% to 8%) and a high intake of unsaturated fatty acids.
Exercise Management
Moderate-intensity aerobic exercise, such as jumping rope, jogging, brisk walking, skating, playing tai chi, etc., is recommended at least 5 days a week, with at least 30 minutes of exercise each time if possible.
Disease Monitoring
Daily monitoring of body weight, waist circumference, blood pressure, blood glucose, and blood lipids is recommended for patients with metabolic syndrome to keep them at reasonable targets.
Body weight: It is recommended to monitor body weight so that it can be reduced by 7% to 10% within 1 year, and strive to achieve a normal body mass index, i.e., BMI <24 kg/m2.
Waist circumference: It is recommended to monitor the waist circumference so that it is <90 cm for men and <85 cm for women.
Blood pressure: Daily monitoring of blood pressure is recommended to be <140/90 mmHg for non-diabetic patients and <130/80 mmHg for diabetic patients.
Blood glucose: Fasting and postprandial blood glucose monitoring is recommended; fasting blood glucose <6.1 mmol/L, postprandial 2h blood glucose <7.8 mmol/L.
Lipids: It is recommended to monitor blood lipids annually and regularly during drug treatment, so that LDL cholesterol <2.60 mmol/L, triglycerides <1.70 mmol/L, HDL cholesterol >1.04 mmol/L (male) or >1.30 mmol/L (female).
Follow-up
Patients with metabolic syndrome are recommended to follow up regularly at the endocrinology and cardiovascular medicine clinics. Blood glucose, blood lipids, liver function, renal function, glycosylated hemoglobin, etc., as well as ambulatory blood pressure, abdominal ultrasound and other examinations should be reviewed.
Prevention
Prevention of metabolic syndrome focuses on maintaining a healthy lifestyle and losing weight.
Maintaining an ideal body weight and exercising appropriately advocate moderate-intensity aerobic exercise, such as jumping rope, jogging, brisk walking, etc., at least five days a week, for at least 30 minutes each time as far as possible.
Daily diet should be based on low sugar, low salt, low fat, and more intake of high protein, high dietary fiber, high vitamin food.
Maintain a good mood.
Quit smoking and do not drink too much alcohol.