The progressively growing number of patients with end-stage renal failure (
ESRF) associated with diabetes mellitus and requiring renal replacement the
rapy (RRT) stimulated both nephrologists and diabetologists to investigate
the mechanisms linking hyperglycaemia to diabetic renal failure and to set
up measures to prevent the onset and slow the progression of diabetic nephr
opathy. Over the last few decades, a large number of studies have investiga
ted both the incidence of diabetic nephropathy and the relationship between
metabolic control and the development of diabetic nephropathy.
Chronologically, the first type of diabetes and diabetic nephropathy to be
studied was type I, and it is only in recent years that metabolic control h
as been proven to be a contributor to the development of nephropathy in suc
h patients. Recently, the DCCT demonstrated that metabolic control in the p
re-albuminuric phase was effective in reducing the incidence of microalbumi
nuria, even if it was unable to reduce the incidence of overt proteinuria i
n patients with type I diabetes and established proteinuria.
On the other hand, in type II diabetes, the number of studies demonstrating
a favourable effect of metabolic control on onset and progression of diabe
tic nephropathy is only slightly greater than those that failed to show a f
avourable effect. This feature may suggest that in type II patients, geneti
c and ethnic differences, nutritional aspects, lifestyle and other confound
ing factors may play a relevant role in the course of the disease.
However, the trials performed and the retrospective analyses generally agre
e that glycated haemoglobin two standard deviations greater than the mean i
s related to a worsening in progression of diabetic nephropathy and to an e
nhanced risk of other complications. In general, a glycated haemoglobin les
s than or equal to 8% seems advisable. Moreover, in both type I and type II
, greater emphasis should be placed on the major risk factors such as hyper
tension, smoking habits and hyperlipidaemia.