Clinical diabetic nephropathy: natural history and complications.

Diabetic nephropathy develops in about 45% of insulin dependent diabetics of whom two-thirds will develop renal failure, the rest dying from cardiovascular disease. Most of the excess mortality of insulin dependent diabetics occurs in those with proteinuria. Among non-insulin dependent diabetics nephropathy is also an important cause of increased mortality but this is mainly from cardiovascular disease. Once diabetic nephropathy is established it progresses relentlessly to end-stage renal failure over about seven years, but ranging from five to 20 years. The explanation for the different rates of progression in individual patients is not understood. Hypertension accompanies diabetic nephropathy and its treatment may retard the progression of renal failure. Other forms of intervention include glycaemic control which has not been shown to have any effect, and protein restriction for which no conclusions can be drawn at present. The diagnosis of diabetic nephropathy is straightforward in the presence of a typical history and clinical features. Non-diabetic renal disease is sometimes the cause of renal failure and may require specific treatment; prognosis for renal failure treatment may be better than for nephropathy patients with other diabetic complications. Other diabetic complications develop as diabetic nephropathy progresses, most notably cardiac and peripheral vascular disease. Proliferative retinopathy and neuropathy are considerable problems and their management needs attention both before and after renal failure treatment.