Diabetic nephropathy - Stages

The stages of development and the “natural” course of diabetic nephropathy have been studied in more detail in type 1 diabetes mellitus, which is associated with the possibility of almost accurately recording the time of onset of diabetes mellitus.

The modern classification of stages of development of diabetic nephropathy was developed by the Danish researcher C.E. Mogensen in 1983.

Stages of development of diabetic nephropathy proposed by C. E. Mogensen (1983)

Stage of diabetic nephropathy	Main characteristics	Time of occurrence from the onset of diabetes mellitus
I. Hyperfunction of the kidneys	Hyperfiltration, hyperperfusion, renal hypertrophy, normoalbuminuria (less than 30 mg/day)	The debut of diabetes
II. Initial structural changes in the kidneys	Thickening of the glomerular basement membrane Mesangial expansion, hyperfiltration, normoalbuminuria (less than 30 mg/day)	More than 2 years More than 5 years
III. Incipient diabetic nephropathy	Microalbuminuria (30 to 300 mg/day), normal or moderately elevated SCF	More than 5 years
IV. Severe diabetic nephropathy	Proteinuria, hypertension, decreased glomerular filtration rate, sclerosis of 50-75% of glomeruli	More than 10-15 years
V. Uremia	SCF less than 10 ml/min, total glomerulosclerosis	More than 15-20 years

Proteinuria, the first clinical sign of a pathological process in the kidneys, appears only in stage IV of diabetic nephropathy. The first three stages are asymptomatic and do not manifest clinically. These three stages constitute the so-called "asymptomatic, preclinical" period of diabetic nephropathy. During this period, all functional changes in the kidneys (hyperfiltration, renal hyperperfusion, microalbuminuria) cannot be detected during routine examination of patients and require the use of special methods. The tactics of examination using special methods is justified by the fact that only these first three (asymptomatic) stages of diabetic nephropathy can be reversible with careful and early correction of hyperglycemia.

The appearance of proteinuria indicates that about 50% of the glomeruli are already sclerosed and the process in the kidneys has become irreversible. From the moment proteinuria appears in diabetes mellitus, the SCF begins to decrease with a mathematically calculated value of 1 ml/min per month (or about 10-15 ml/min per year), which leads to the development of terminal renal failure already 5-7 years after the detection of persistent proteinuria. At this stage, even the most careful correction of carbohydrate metabolism disorders is no longer able to stop or significantly slow down such a rapid progression of diabetic nephropathy.

From the onset of diabetes mellitus, the stage of microalbuminuria develops, as a rule, after 5 years, the stage of proteinuria - after 15-20 years, the stage of chronic renal failure - after 20-25 years.

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