Treatment of diabetic complications: Lowering blood pressure is more important than lowering blood sugar.

Why is lowering blood pressure more important than lowering blood sugar in the drug treatment of patients with diabetes and hypertension?

It's generally believed that the most important thing for someone with diabetes is to lower blood sugar, often neglecting to control blood pressure. In fact, for patients with both diabetes and hypertension, while lowering blood sugar is important, controlling blood pressure within a normal range is even more crucial. Increasing clinical practice both domestically and internationally shows that hypertension and diabetes are like twins, both being major risk factors for metabolic syndrome. Regardless of which disease occurs first, both will exacerbate damage to target organs such as the heart, brain, kidneys, and blood vessels. The UK Prospective Diabetes Study showed that strict blood pressure control can reduce any diabetes-related endpoint event (i.e., complications such as myocardial infarction and stroke) by 24%, and diabetes-related mortality by 32%, including a 44% reduction in stroke incidence and a 37% reduction in microvascular disease. In contrast, strict blood glucose control only reduced any diabetes-related endpoint event by 12%, microvascular disease by 25%, and myocardial infarction by 16%. Diabetic patients need to control their blood pressure lower than those with hypertension, specifically below 130/80 mmHg. Clinical practice has shown that the greatest threat to type 2 diabetes patients is not microvascular disease directly related to high blood glucose, but rather macrovascular disease, such as cardiovascular and cerebrovascular diseases and peripheral arterial occlusive disease. More than 80% of diabetes deaths are due to cardiovascular disease. The benefits of lowering blood pressure for diabetic patients are twice that of lowering blood glucose. Therefore, strict blood pressure control is more significant for diabetic patients than intensive blood glucose control. Which antihypertensive drugs are suitable for diabetic patients with comorbid hypertension? The antihypertensive drugs chosen for diabetic patients with hypertension are the same as those chosen for patients with hypertension and diabetes.

What precautions should be taken when treating diabetes with hypertension?

① Start with a low dose. If the effect is unsatisfactory, the dose can be increased or other antihypertensive drugs can be combined.

② Blood pressure control requires 24-hour stability; therefore, long-acting preparations taken once daily should be used whenever possible.

③ Some drugs affect blood sugar. For example, high-dose hydrochlorothiazide can raise blood sugar levels. Non-selective beta-blockers (such as propranolol) can mask early symptoms of hypoglycemia; therefore, these two drugs should be used with caution.

④ ACEIs and ARBs are currently recognized as the first-line drugs for diabetes with hypertension. These drugs can reduce urinary microalbumin, delay the onset and progression of kidney disease, and reduce the incidence of heart failure and myocardial infarction.

⑤ Diabetic patients are prone to orthostatic hypotension. Therefore, after taking antihypertensive drugs, attention should be paid to changes in blood pressure in lying, sitting, and standing positions. Change positions slowly to prevent syncope.

⑥ Once hypertension is diagnosed, medication and lifelong treatment are essential.

Can patients with diabetes and hypertension use the beta-blocker metoprolol (Betaloc) to lower blood pressure?

Diabetic patients can use metoprolol to lower blood pressure, but it needs to be taken in low doses, and blood glucose and heart rate should be monitored. Whether diabetic patients can use beta-blockers is a frequently encountered clinical issue that requires weighing the risks and benefits. Because beta-blockers can affect glucose metabolism and mask symptoms of hypoglycemia, their use in diabetic patients is questionable. However, some large clinical studies have confirmed that for patients with diabetes and hypertension, or diabetes and myocardial infarction, beta-blockers can significantly improve prognosis and reduce cardiovascular events, showing that the benefits outweigh the risks.

Can patients with diabetes and hypertension use thiazide diuretics to lower blood pressure? Thiazide diuretics (such as hydrochlorothiazide) can interfere with glucose metabolism, causing decreased insulin secretion, abnormal glucose metabolism, decreased blood potassium, and increased total cholesterol and triglycerides. Studies have shown that 30% of patients using hydrochlorothiazide long-term, high-dose use may develop impaired glucose tolerance, with elevated fasting and postprandial blood glucose levels. However, recent studies have found that low-dose hydrochlorothiazide (12.5 mg daily) has a similar antihypertensive effect to high-dose (25 mg), while having minimal impact on glucose and lipid metabolism. It can also protect cardiac function, correct heart failure, reduce the incidence of cardiovascular events, and delay the onset and progression of diabetic nephropathy. Therefore, low-dose hydrochlorothiazide can be used in diabetic patients with hypertension, especially those with kidney damage and cardiovascular complications. The main adverse reaction is hypokalemia, which should be monitored promptly.

Which lipid-lowering drugs should be chosen for diabetic patients with dyslipidemia?

The lipid-lowering drugs for diabetic patients are largely the same as those for ordinary dyslipidemia patients; the main difference lies in selecting appropriate drugs based on the type of dyslipidemia.

① Patients with high cholesterol or high-density lipoprotein cholesterol should use statins, such as lovastatin (Mecliz), simvastatin (Zocor), pravastatin (Pracou), fluvastatin (Lescol), and atorvastatin (Lipitor). These drugs primarily lower cholesterol, reducing it by 20%–30%, and can also slightly increase high-density lipoprotein cholesterol and slightly lower triglycerides.

② Patients with high triglycerides should use fibrates, such as fenofibrate (Lipoxetine), bezafibrate (Bicariin), and gemfibrozil (Norhexine).

③ Patients with both high cholesterol and high triglycerides can use a combination of statins and fibrates. ④ Other options include bile acid sequestrants and niacin.

Will blood lipids return to normal after blood sugar is controlled in diabetic patients?

Diabetic patients often have dyslipidemia, and this dyslipidemia is related to the quality of blood sugar control. This means that after blood sugar is controlled, dyslipidemia will definitely improve to some extent. However, not all diabetic patients will have their dyslipidemia completely return to normal after blood sugar control. This is because dyslipidemia in diabetic patients is caused by multiple factors, and elevated blood sugar is only one of them. Studies have observed that for type 1 diabetic patients, dyslipidemia often returns to normal after blood sugar control; while for type 2 diabetic patients, dyslipidemia only partially returns to normal in most cases after blood sugar control. Therefore, type 2 diabetic patients often need to take lipid-lowering drugs simultaneously.

Why should statins be the first choice for lipid-lowering treatment in diabetic patients with dyslipidemia?

Statins are widely used in type 2 diabetic patients to prevent cardiovascular disease. Research suggests that controlling high-risk factors for cardiovascular disease (especially high blood pressure and cholesterol levels) is just as important as controlling blood sugar levels. The poor prognosis of diabetes stems from complications of microvascular disease or macrovascular disease. Microvascular complications include retinopathy and nephropathy, while macrovascular complications include coronary artery disease, peripheral vascular disease, and cerebrovascular disease. Some studies confirm that 80% of diabetic patients die from macrovascular complications. Therefore, the American College of Physicians recommends the following:

① All adults diagnosed with coronary artery disease and type 2 diabetes should receive statins as secondary prevention of cardiovascular disease.

② All patients with type 2 diabetes and other high-risk factors for cardiovascular disease (including hypertension, smoking, left ventricular hypertrophy, and age over 55) should receive statins as primary prevention of macrovascular disease.

③ Patients already receiving statin therapy should take at least a moderate dose, i.e., atorvastatin 20 mg once daily; lovastatin 40 mg once daily. The dosage is 40 mg of pravastatin or simvastatin once daily.

How should blood sugar be lowered in patients with diabetes and coronary heart disease?

Coronary heart disease is a major macrovascular complication of diabetes. According to literature, up to 72.3% of diabetic patients also have coronary heart disease, and approximately 50% of type 2 diabetic patients already have coronary heart disease at diagnosis. Furthermore, diabetes itself accelerates the development of coronary heart disease. About 80% of diabetic patients die from cardiovascular complications, of which 75% die from coronary heart disease, 2 to 4 times higher than in non-diabetic patients. Therefore, actively treating diabetes, preventing and delaying the development of coronary heart disease, and reducing the mortality rate of diabetic patients are crucial. The primary disease must be treated first; in cases of diabetes complicated by coronary heart disease, diabetes should be treated first. Blood sugar control standards should be individualized and adjusted according to each patient's specific situation. For younger patients with mild complications, the goal is to maintain blood sugar levels within the normal range. For older patients with severe heart disease (such as severe arrhythmias, heart failure, large-area myocardial infarction, frequent angina), blood sugar control should be within the normal range, with fasting blood sugar around 7.0 mmol/L and postprandial blood sugar not exceeding 10 mmol/L. It is crucial to avoid excessively high or low blood sugar levels that could trigger a heart attack and worsen the condition. For patients in the acute phase of myocardial infarction or with severe heart disease, insulin therapy is recommended. For patients with milder heart disease or stable conditions, appropriate oral hypoglycemic agents can be selected based on their individual circumstances. Secondly, risk factors should be controlled. For those with lipid metabolism disorders, lipid-lowering therapy should be actively pursued. For those with high blood pressure, blood pressure should be strictly controlled to below 130/80 mmHg, and ACE inhibitors or arteriovenous renin-angiotensin II (ARB) drugs should be used. Other measures should be administered symptomatically according to the patient's coronary artery disease condition. Examples of hypoglycemic agents include vasodilators (nitrates), antiplatelet drugs (aspirin, clopidogrel), thrombolytics, and anticoagulants.

How should hypoglycemic drugs be selected for patients with diabetes and nephropathy?

For patients with diabetes and nephropathy, glimepiride (Gluconate) is the first choice because it does not affect kidney function, has a low probability of hypoglycemic reactions, and is mainly excreted in the liver and gallbladder, with only 5% excreted through the kidneys, which helps improve renal blood flow. It can also be taken by patients with mild to moderate renal impairment. The dosage is 30mg once before each of the three meals. Alternatively, it can be 15mg three times a day. Given that insulin sensitizers can reduce the level of vascular cell adhesion molecules, thus improving abnormal lipid metabolism, inhibiting total cholesterol absorption, lowering blood lipid levels and the proportion of lipoproteins, and reducing the occurrence of diabetic vascular complications and diabetic nephropathy, it is recommended to use insulin sensitizers such as rosiglitazone (Avandia) or pioglitazone (Aitine) as early as possible.