Diabetic complications and current management

Kidney and cardiovascular complications

There have been many recent developments in our understanding of diabetic kidney complications and they can now be managed much more effectively than, say, 20 years ago. This is reflected in figures that suggest that in type 1 diabetes the number of people developing kidney damage has declined from 35-40 per cent in the 1980s to around 25 per cent today. This decline is very encouraging when it is remembered that kidney complications in diabetes is one of the leading causes of kidney failure in the Western world. In type 2 diabetes, kidney complications are less common than in type 1, but because of the much greater number of people with type 2 diabetes, the total number with kidney problems is also greater.

The diagnosis of kidney problems is relatively straightforward and is based on the presence of protein in the urine (called proteinuria), usually coupled with high blood pressure, and other evidence of declining kidney function. Control is important, because people with protein in the urine are at higher risk from eye, nerve and heart disease. Once diagnosed, the doctor will seek to improve the control of blood glucose and prescribe medicines for high blood pressure.

Improvement in blood glucose may require changes in the medication prescribed – perhaps varying the sulphonylurea, biguanide or glitazone to give better 24 hour coverage, or by adding in short and/or long-acting insulins if these are not being used. This will be coupled with intensive patient education to drive home the vital importance of blood glucose self-monitoring, exercise, and stopping smoking. In type 1 diabetes, this approach is known to reduce the progression to clinically significant kidney damage by as much as 54 per cent – a figure that probably applies also to type 2 diabetes, although data is still lacking.

For blood pressure, the doctor is likely to prescribe one of the angiotensin converting enzyme (ACE) inhibitors. These help reduce blood pressure and cardiovascular events, stabilise the kidney and delay deterioration by reducing blood pressure in the kidneys. For optimum control, though, a second or even third medicine may be needed. This will most likely be either a long-acting calcium channel blocker, or a beta blocker acting selectively on the heart. It may also be necessary to prescribe a medicine that increases the rate of fluid excretion from the kidneys (a diuretic) and possibly a medicine to reduce cholesterol and fatty materials in the blood (e.g. one of the ‘statin’ type of medicines such as atorvastatin from Parke-Davis, fluvastatin from Novartis or MSD’s simvastatin). In combination, these will regulate blood pressure and blood fat levels and help slow further kidney deterioration. However, it should be emphasised that the choice and combination used will depend on the severity of the diabetes and the age and general health of the individual.