Diabetic nephropathy (DN) is one of the common chronic complications of diabetes mellitus, which refers to the kidney damage caused by diabetes mellitus itself, clinically marked by the presence of persistent proteinuria as the main hallmark. In developed countries and regions such as Europe and the United States, DN has become the primary cause of end-stage renal disease (ESRD), with 44% of newly diagnosed ESRD patients in the United States having DN in 1997; in Hong Kong and Taiwan, DN accounts for more than 20% of ESRD; with economic development and longer life expectancy, the prevalence of DN in China’s inland areas is increasing dramatically and has become the second leading cause of ESRD (after primary glomerulonephritis), accounting for about 5-10%, and the proportion will increase with the westernization of lifestyle. Among diabetic patients, the incidence of DN is about 34.7%, second only to cardiovascular disease. DN poses a threat to the health and life of patients and a huge economic burden to society and families, but it can be prevented and treated in the early stage.
DN has the following clinical features.
1. Chronic progression of the natural course of the disease: the course of the disease extends for several years, decades or longer;
2, insidious onset: early asymptomatic, only through the urine and other auxiliary examination to detect renal pathological changes, easy to lose the best time for early intervention;
3, poor prognosis: once early DN develops to clinical symptoms, it cannot be reversed and eventually progresses to ESRD, which must rely on renal replacement therapy to maintain life. Therefore, early prevention and treatment can receive twice the result with half the effort.
The early diagnosis of DN must rely on laboratory tests. Routine urine examination is a mandatory initial screening test. If urine protein is characterized as negative, urine microalbumin should be further examined. If the UAE is less than 20μg/min, it is normal albuminuria; if the UAE is between 20 and 200μg/min, it is microalbuminuria, which is the clinical diagnosis of early DN. Clinical DN is diagnosed when UAE is consistently >200 μg/min or routine 24 h urine protein quantification >0.5 g. For early detection and diagnosis of DN, the American Diabetes Association (ADA) recommends annual screening for newly diagnosed type 2 diabetics and annual screening for type 1 diabetes 5 years after diagnosis.
The main goal of prevention and treatment of diabetic nephropathy is to prevent the occurrence and progression of DN, with emphasis on prevention. There is no specific method for treatment, and currently a comprehensive treatment approach is used to control risk factors that may lead to progression of the disease. Including the following aspects.
1.Control of blood sugar
High blood sugar is the initiating factor for various pathological changes in DN. Intensive glycemic control can delay the occurrence of microalbuminuria in type 1 and type 2 diabetic patients and slow down the progression of microalbuminuria to clinical proteinuria. The necessity of insulin use is not emphasized in the choice of medication. The selection of glucose-lowering drugs in clinical practice should be based on the patient’s complications, age and other factors to consider the type of drug selected, the dose and the target value of intensive glycemic control. In order to prevent the occurrence of microproteinuria as much as possible, it is recommended that glycemic control should be intensified as early as possible.
2.Dietary treatment
Low protein diet can reduce urinary protein excretion and slow down the deterioration of renal function in DN patients. The protein intake of early DN patients should be controlled at the normal low limit [0.8-1.0g/(kg・d)]; in renal insufficiency, the protein intake should be controlled between 0.6-0.8g/(kg・d), and animal protein should be the mainstay. To avoid the occurrence of malnutrition, adequate caloric intake should be ensured during the low-protein diet. Patients who have the condition can add alpha-keto acid preparation. In addition, DN patients should also appropriately reduce salt in the diet and eat less food containing high purine, such as animal offal, seafood, beer, etc.
3.Improve lifestyle
Smoking is an independent risk factor for the progression of type 2 diabetes to DN and is associated with deterioration of kidney function. Quitting smoking can reduce the risk of DN progression by 30%. Therefore, it is recommended that all diabetic patients should quit smoking. Weight control is also an important measure. One study found that bringing down the body mass index of overweight patients can achieve stabilization of renal function and significant reduction of proteinuria. It is recommended that DN patients control their body mass index at 18.5 to 24.9 [body mass index = weight (kg)/height (m2)].
4. Control blood pressure
High blood pressure plays a key role in the progression of renal failure. strict control of blood pressure is as important as strict control of blood glucose to delay the development of diabetic complications. the lower the blood pressure control in DN patients, the slower the rate of decline of renal function. It is recommended that patients with DN should have blood pressure below 130/80 mmHg, a lower level than that controlled in patients without diabetes. In terms of antihypertensive drug selection, angiotensin-converting enzyme inhibitor (ACEI) or angiotensin II receptor antagonist (ARB) should be the first choice, combined with 2 or more antihypertensive drugs (including calcium channel blockers, diuretics, B-blockers, etc.) if necessary, with attention to monitoring renal function and changes in blood potassium.
5.Lipid regulating treatment
Diabetic patients are often accompanied by disorders of lipid metabolism, hyperlipidemia can also accelerate the decline of renal function and increase the death rate of DN. Hyperlipidemia can be improved through reasonable diet, weight loss and blood glucose control. When the goal cannot be achieved through blood glucose control and diet therapy, lipid-lowering drugs can be administered. For triglyceride elevation, use fibrates, and for cholesterol elevation, use statins. The recommended treatment criteria are: total cholesterol <4.5mmol/L, low-density lipoprotein cholesterol (LDL-C) <2.6mmol>1.1mmol/L, triglyceride (TG) <1.5mmol/L.
6.Control proteinuria
Proteinuria is not only a clinical manifestation of DN, but also an important risk factor for promoting deterioration of renal function and increasing cardiovascular events. It is recommended that diabetic patients with normal blood pressure should also be treated with ACEI or ARB to reduce the excretion rate of albumin in urine.
7. Certain measures to reduce vascular lesions
The application of antithrombotic drugs (such as aspirin and dipyridamole) or blood-activating herbs can slow down the progression of some DN patients.
In conclusion, the key to diabetic nephropathy lies in early and comprehensive prevention and treatment. The general public should pay more attention to their own health, have regular medical checkups, seek medical advice when problems are detected, and follow medical advice strictly to prevent the problem before it happens.