Evolution Of Diabetic Nephropathy

Diabetic renal disease is characterised by changes in both AER and GFR in predisposed patients. The usual sequence starts with an increase in GFR (hyperfiltration), followed by an increase in AER leading to microalbuminuria. Hyperfiltration may persist through the phase of microalbuminuria or it may normalise prior to the onset of overt nephropathy (macroalbuminuria), which is accompanied by further increases in AER and a declining GFR. In parallel with these changes, there is a rise in blood pressure which may begin before the development of microalbuminuria in type 2 diabetes but usually occurs during the early microalbuminuric phase in type 1 diabetes.

The above process evolves over 10-15 years and is generally similar in type 1 and type 2 diabetes, with some differences (Figure 1).

The major clinically identifiable initiators are hyperglycaemia and blood pressure control. Increases in AER into the microalbuminuric range may occur transiently with exercise, urinary tract infection, uncontrolled hyperglycaemia and cardiac failure, and on a long-term basis with hypertension, non-diabetic renal disease, and in association with large vessel disease. However, progression to overt diabetic nephropathy does not occur without long-term hyperglycaemia. Following the onset of overt nephropathy there is usually a close coupling of increases in AER with decreases in GFR. The subsequent rate of decline of GFR is influenced by several progression promoters including the level of blood pressure, hyperglycaemia and proteinuria, as well as retinopathy and smoking. Recent evidence suggests that a decline in GFR may occur, less commonly, in subjects with minimal or no increases in AER. This raises the question of whether the sequence of microalbuminuria leading to macroalbuminuria is itself a cause of renal injury resulting in a GFR decline, or whether changes in AER and GFR are both secondary to underlying renal structural changes.

Type 2 Diabetes
Diabetic Nephropathy Evolution

Figure 1. Blood pressure and GFR during normo-, micro- and macroalbuminuria in type 1 and type 2 diabetes.

Diabetes 2

Diabetes 2

Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...

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