From the Guidelines
Diabetic nephropathy is characterized by a range of symptoms and diagnostic findings, including microalbuminuria, proteinuria, declining glomerular filtration rate (GFR), hypertension, and edema, with definitive diagnosis relying on laboratory findings such as elevated urine albumin-to-creatinine ratio (UACR) and reduced estimated GFR. The earliest detectable sign of diabetic nephropathy is microalbuminuria, defined as 30-300 mg/day of albumin in urine 1. As the disease progresses, symptoms include persistent proteinuria (>300 mg/day), gradually declining GFR, hypertension, and edema, particularly in the lower extremities. Later stages may present with symptoms of uremia such as fatigue, nausea, pruritus, and confusion.
Key diagnostic findings include:
- Elevated UACR on spot urine samples, with values of 30-300 mg/g indicating microalbuminuria and >300 mg/g indicating macroalbuminuria 1
- Serum creatinine elevation and reduced estimated GFR (<60 mL/min/1.73m²) confirm declining kidney function
- Renal ultrasound typically shows normal or enlarged kidneys in early stages, with eventual kidney shrinkage in advanced disease
- The presence of diabetic retinopathy strengthens the diagnosis, as both conditions share similar microvascular pathophysiology
The underlying mechanism involves hyperglycemia-induced damage to glomerular capillaries, leading to basement membrane thickening, mesangial expansion, and eventual glomerulosclerosis, which progressively impairs kidney function 1. The diagnosis and management of diabetic nephropathy should be based on the latest clinical guidelines, which recommend the use of sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide 1 receptor agonists to provide both kidney and cardiovascular protective benefits.
Some key points to consider in the diagnosis and management of diabetic nephropathy include:
- The importance of early detection and diagnosis, as this can help to slow the progression of the disease
- The use of laboratory findings, such as UACR and estimated GFR, to confirm declining kidney function
- The presence of diabetic retinopathy, which can strengthen the diagnosis and indicate similar microvascular pathophysiology
- The latest clinical guidelines, which recommend the use of sodium-glucose cotransporter 2 inhibitors and glucagon-like peptide 1 receptor agonists to provide both kidney and cardiovascular protective benefits 1.
From the Research
Symptoms of Diabetic Nephropathy
- Persistent albuminuria, which is a key component of diabetic nephropathy 2
- Progressive decline in renal function 3, 4
- Increased urinary albumin excretion 2
- Loss of renal function 2
- Hematuria, which may indicate nondiabetic renal disease in diabetic chronic kidney disease (CKD) 5
Key Diagnostic Findings
- Microalbuminuria, which should be screened annually starting 5 years after diagnosis in type 1 diabetes and at diagnosis and annually thereafter in type 2 diabetes 6
- Proteinuria, which is a key component of diabetic nephropathy 2
- Reduced renal function, which can be measured by estimated glomerular filtration rate (eGFR) 4, 5
- Hematuria, which is associated with an increased risk of end-stage renal disease in patients with early diabetic CKD 5
- Blood glucose and blood pressure control, which are important for diagnosing and managing diabetic nephropathy 6, 4