Is urinalysis recommended in diabetes management?

Urinalysis in Diabetes Management

Annual urinalysis to assess urinary albumin-to-creatinine ratio (UACR) is strongly recommended in all patients with type 2 diabetes and in patients with type 1 diabetes with duration ≥5 years to screen for diabetic kidney disease. 1

Recommended Urinalysis Testing

• At least once a year, quantitatively assess urinary albumin (e.g., spot urinary albumin-to-creatinine ratio) and estimated glomerular filtration rate (eGFR) in all patients with type 2 diabetes regardless of treatment duration 1, 2
• For patients with type 1 diabetes, begin annual urinary albumin testing after 5 years of diabetes duration 1
• Due to high biological variability in urinary albumin excretion, two of three specimens collected within a 3-6 month period should be abnormal before confirming the diagnosis of albuminuria 2

Classification of Albuminuria

• Normal UACR: <30 mg/g creatinine 2
• Moderately increased albuminuria: 30-299 mg/g creatinine 2
• Severely increased albuminuria: ≥300 mg/g creatinine 2

Clinical Significance and Management

• Diabetic kidney disease occurs in 20-40% of patients with diabetes and is the leading cause of end-stage renal disease 1
• Persistent increased albuminuria is an early indicator of diabetic kidney disease in type 1 diabetes and a marker for development of diabetic kidney disease in type 2 diabetes 1
• Albuminuria is a well-established marker of increased cardiovascular disease risk 1
• For patients with established diabetic kidney disease, UACR should be monitored 1-4 times per year depending on disease stage 2

Treatment Based on Urinalysis Results

• For patients with moderately increased albuminuria (30-299 mg/g), an ACE inhibitor or ARB is recommended 1, 2
• For patients with severely increased albuminuria (≥300 mg/g), an ACE inhibitor or ARB is strongly recommended 1
• ACE inhibitors or ARBs are not recommended for primary prevention of diabetic kidney disease in patients with normal blood pressure and normal UACR (<30 mg/g) 1, 2
• When ACE inhibitors, ARBs, or diuretics are used, monitor serum creatinine and potassium levels for adverse changes 1

Additional Considerations

• Factors that can temporarily elevate UACR include exercise within 24 hours, infection, fever, congestive heart failure, marked hyperglycemia, menstruation, and marked hypertension 2
• Optimize glucose control to reduce the risk or slow the progression of diabetic kidney disease 1
• Optimize blood pressure control to reduce the risk or slow the progression of diabetic kidney disease 1
• Dietary protein intake should be approximately 0.8 g/kg body weight per day for patients with non-dialysis dependent diabetic kidney disease 1, 2

Important Pitfalls to Avoid

• Urine glucose tests should never be used to evaluate diabetes control or management as they are not reliable or accurate indicators of blood glucose levels 1
• Do not rely on a single positive UACR test; confirm with 2-3 specimens over 3-6 months due to high biological variability 2
• Do not discontinue renin-angiotensin system blockade for minor increases in serum creatinine (<30%) in the absence of volume depletion 2
• Patients with diabetes are at increased risk for urinary tract infections; microscopic urinalysis and culture are essential in assessing patients with diabetes who have urinary symptoms 1, 3

When to Refer to Nephrology

• Refer patients to a nephrologist if eGFR <30 mL/min/1.73m² 2
• Consider referral when there is uncertainty about the etiology of kidney disease, difficult management issues, or rapidly progressing kidney disease 1, 2