- Click here for explanation of classification scheme.

A position paper was developed to make information more available to the professional and public, about abnormal quantities of protein in the urine identifying those at increased risk for myocardial infarction and stroke, and that intensive management of such risk factors as high blood pressure and abnormal lipids may benefit these high risk individuals.

Three separate panels of experts and invited participants addressed issues related to proteinuria as a risk factor for cardiovascular disease, as a mediator and marker of progressive kidney failure, and (persistent massive proteinuria) as the inciting factor that leads to nephrotic syndrome.

Not specified.

Recruitment: Three separate panels of experts and invited participants addressed issues related to proteinuria as a risk factor. These expert recommendations were presented at four Town Hall Meetings for additional input, comment, or modification. These revised recommendations were submitted for review by the Scientific Advisory Board of the NKF and adopted by the Board of Directors on 10/23/1998.

Design:  Consensus Report. 

Blinding Used (if appliable): not applicable

Intervention (if applicable): not applicable

Statistical Analysis: not applicable

Timing of Measurements: not specified

Dependent Variables:

• Proteinuria
• Albuminuria

Independent Variables: not specified

Control Variables: not specified

 

Initial N: not applicable

Attrition (final N): not applicable

Age: not applicable

Ethnicity: not applicable

Other Relevant Demographics: not applicable

Anthropometrics: not applicable

Location: not applicable

 

Microalbuminuria

Microalbuminuria is an independent risk factor for the outcome of both kidney and CVD.

Testing for proteinuria/albuminuria

1. Proteinuria

a. routine urinalysis: if proteinuria is detected on any evaluation of the urine, dipstick analysis should be repeated on at least 1 additional sample within the next 3 months.

b. “spot” urine protein/creatinine ratio: quantification of proteinuria; normal range is <200 mg urine protein/g urine creatinine

2. Albuminuria

a. “spot” urine albumin/creatinine ratio: assesses risk of glomerulopathy in diabetes and CVD in hypertensives.

b. normal range: <30 mg urinary albumin/g urine creatinine on first morning urine.

3. Quantification of urinary protein and creatinine:

a. 24-hr urine collection is more accurate than spot urine but is inconvenient for the patient. (Normal range: <150 mg protein/24-hr)

b. when proteinuria coexists with increased serum creatinine (>1.4 mg/dL, men; >1.2 mg/dL, women) or hypertension (>140/90 mm Hg) patients are at increased risk for loss of kidney function.

c. Also useful in quantifying dietary sodium, potassium, protein and creatinine clearance.

Proteinuria and CVD

Microalbuminuria in high-risk individuals is an independent risk factor of CVD (MI or stroke) and when present, the patient needs more intensive therapy and closer follow-up.

Clinical situations indicating a higher risk:

Diabetes mellitus

Hypertension

Central obesity

Advanced age

African American

Hispanic

Native American

Pacific Islander

Family history of CVD or renal disease

Therapeutic interventions to reduce proteinuria and slow the progression of renal disease

1. Blood pressure control: <130/85 mm Hg, 125/75 mm Hg preferable

2. Angiotension-converting enzyme inhibitor therapy: Therapy with an angiotension II receptor antagonist is recommended in those patients who are intolerant of angiotension converting enzyme inhibitors.

3. Dietary salt restriction:

A high salt intake can override the antiprotective effects of angiotensionconverting enzyme inhibitors. Salt restriction is especially important in hypertensives with proteinuria.

4. Dietary protein restriction:

Moderate restriction (0.8 g/kg) is recommended in proteinuric patients to assist in decreasing the degree of proteinuria and the progression of renal disease.

Proteinuria in the nephrotic syndrome

1. Nephrotic syndrome is defined as persistent nephrotic range proteinuria (>3 g protein/24-hr urine) and decreased serum albumin.

2. Other metabolic components of nephritic syndrome include: edema, hyperlipidemia, hypercoaguability, muscle wasting, hypocalcemia and vitamin D deficiency.

Nephrology referral and follow-up

1. Since patients with proteinuria are at increased risk for progression to end-stage renal failure, follow-up should be every 3-4 months and include the following:

a. urine protein/creatinine ratio

b. dietary compliance (urine sodium, urea)

c. blood pressure

d. serum albumin and cholesterol

e. serum creatinine

2. Treatment goals:

a. reduction of urinary protein (of 40% to 50%)

b. control blood pressure (<130/75 mm Hg)

c. restriction of dietary sodium and protein (0.8 g/kg body weight)

d. risk management (smoking cessation, serum lipids)

The presence of even relatively small amounts of protein or albumin in the urine is an important early sign of kidney disease and a strong predictor for an increased risk for cardiovascular mortality and morbidity in high-risk groups.

Early detection of proteinuria/albuminuria and institution of appropriate therapy has been show to slow the progression of kidney disease.

Intensive management of high blood pressure and abnormal lipids may decrease the risk for MI and stroke in individuals with proteinuria.

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Good review of importance of monitoring blood pressure and proteinuria for identifying early kidney disease and through preventive measures, slowing the progression of kidney disease.

Strong recommendations for limiting sodium for controlling blood pressure in this population. Less strong recommendation for limiting protein intake.