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Diabetic Nephropathy (Kidney Damage)

Diabetic nephropathy is a progressive and serious disease of the kidneys in which the small blood vessels of these organs become damaged and begin to leak. As a result, a protein called albumin is lost or excreted in the urine in increasing amounts. When the loss is still at a relatively low level (30 to 300 mg/day), the condition is called microalbuminuria and this is the earliest stage that can be detected by sensitive clinical tests. At a higher level of loss, greater than 300 mg/day, the condition becomes known as proteinuria, a stage that can be detected by urine dipstick (albustix) testing. In fact, five progressive stages of diabetic nephropathy, which overlap with one another, are recognized.

Increase in blood plasma flow to kidneys, which may themselves be slightly enlarged. These are sub-clinical signs that are usually reversible with good control of glycaemia. There are no symptoms.
Early structural changes to kidneys which may develop after about two years. Again, a sub-clinical stage that does not produce symptoms.
Microalbuminuria. Detected either by sensitive radioimmunoassay testing or by measuring albumin/creatinine (a metabolic compound) ratio. Does not produce symptoms but blood pressure is often raised.
Proteinuria. Detected by positive albustix (dipstick) testing. This is the stage that is called clinical nephropathy. It is accompanied by high blood pressure and elevated levels of creatinine.
End-stage renal failure (ESRF). Kidney failure, requiring continual, ongoing treatment.

Nephropathy can have causes other than diabetes, and diagnosis of microalbuminuria is associated with a higher risk of heart and circulatory disease. In diabetes, microalbuminuria is linked with an increased risk of neuropathy and peripheral vascular disease. In addition, there is a close association between nephropathy and retinopathy. About 66 per cent of people with proliferative retinopathy also have associated nephropathy. High blood pressure is another closely associated risk factor.

Nephropathy occurs in about one-third of people with Type 1 diabetes, and, overall, a similar proportion of those with Type 2 syndrome are likewise affected. About one-quarter of white Europeans with Type 2 diabetes are affected by nephropathy but for people of Asian, African, Afro-Caribbean, Native Indian and Japanese descent, the incidence is much higher. Up to half of people in these racial groups are at risk of developing the condition.

See more diabetic complications information.