Diabetes Kidney Disease – Diabetic Nephropathy

What is diabetic nephropathy?

Nephropathy is the deterioration of the kidneys. The final stage of nephropathy is called end-stage renal disease, or ESRD. Diabetes is the most common cause of ESRD, accounting for more than 44 percent of cases.

There are five stages of diabetic nephropathy, or deterioration of the kidneys. The fifth stage is ESRD. Progress from one stage to the next can take many years, with 23 years being the average length of time to reach stage five.

Diabetic nephropathy is a clinical syndrome characterized by persistent albuminuria (>300 mg/d or >200 mcg/min) that is confirmed on at least 2 occasions 3-6 months apart, a relentless decline in the glomerular filtration rate (GFR), and elevated arterial blood pressure

This increase in blood pressure causes the kidneys to filter too much blood, overworking and damaging the nephron. This condition is known as diabetic nephropathy. Because the nephron’s glomeruler filters no longer work, waste begins building up in the body when it should be filtered out, and important blood proteins that should be retained are lost.

Symptoms of Diabetic Nephropathy

Symptoms of this disorder often do not appear until 80 percent of the kidneys have been damaged. When they do appear, symptoms often include swelling, fatigue, loss of appetite, high blood pressure, excessive urination and excessive thirst.

Kidney Failure From Diabetic Nephropathy

When 85 to 90 percent of kidney function is lost, the term “end stage kidney failure” is used, and kidney dialysis or transplant becomes necessary.

Preventing Diabetic Nephropathy

About 10 to 20 percent of all diabetics will develop nephropathy, but a healthy lifestyle can delay or even prevent the condition. This includes carefully controlling glucose levels, staying active, keeping blood pressure in a healthy range and maintaining a healthy weigh.

The onset and progression of diabetic nephropathy can be slowed by intensive management of diabetes and its symptoms, including taking medications to lower blood pressure.

Treatment for diabetic nephropathy:

Several issues are key in the medical care of patients with diabetic nephropathy

Glycemic control

In persons with either IDDM or NIDDM, hyperglycemia has been shown to be a major determinant of the progression of diabetic nephropathy. The evidence is best reported for type 1 diabetes mellitus.

It has been shown that intensive therapy can partially reverse glomerular hypertrophy and hyperfiltration, delay the development of microalbuminuria, and stabilize or even decrease protein levels in patients with microalbuminuria.

Results from pancreatic transplant recipients in which true euglycemia is restored suggest that strict glycemic and metabolic control may slow the progression rate of progressive renal injury even after overt dipstick-positive proteinuria has developed.

Antihypertensive Treatment

Antihypertensive treatment attenuates the rate of decline in renal function in patients who have IDDM, hypertension, and proteinuria. This is particularly significant when lowering of systemic blood pressure is accompanied with concomitant lessening of glomerular capillary pressure.

In general, antihypertensive therapy, irrespective of the agent used, slows the development of diabetic glomerulopathy; however, ACE inhibitors confer superior long-term protection.

Dietary protein Intake:

A meta-analysis examining the effects of dietary protein restriction (0.5-0.85 g/kg/d) in diabetic patients suggested a beneficial effect on the GFR, creatinine clearance, and albuminuria. However, a large, long-term prospective study is needed to establish the safety, efficacy, and compliance with protein restriction in diabetic patients with nephropathy. Limitations include ensuring compliance in the patients.

Specific Therapies:

This includes modification and/or treatment of associated risk factors such as hyperlipidemia, smoking, and hypertension.

Renal Replacement Therapies

i. As for any other patient with ESRD, diabetic patients with ESRD can be offered hemodialysis, peritoneal dialysis, kidney transplantation, or combined kidney-pancreas transplantation.

ii. In patients with uremia of any cause, starting at a creatinine clearance of 10-15 mL/min is wise. In diabetic patients, starting earlier is useful when hypervolemia renders blood pressure uncontrollable, when the patient experiences anorexia and cachexia or other uremic symptoms, and when severe vomiting is the combined result of uremia and gastroparesis.

In principle, diabetic patients who require renal replacement therapy have the following 4 options:

i. Refusal of further treatment for uremia, leading to a progressive decline in general health and ultimately leading to death
ii. Peritoneal dialysis (e.g. machine-assisted intermittent peritoneal dialysis, continuous ambulatory peritoneal dialysis, continuous cyclic peritoneal dialysis)
iii. Hemodialysis (e.g. facility hemodialysis, home hemodialysis)
iv. Renal transplantation (e.g. cadaver donor kidney, living related-donor kidney, living unrelated-donor kidney [emotionally related donor], living unrelated-donor kidney [unrelated by family or emotionally; the so-called altruistic donor], pancreas plus kidney transplantation)