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Diabetes mellitus
Renal protocols
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What are we looking for?
Microalbuminuria, proteinuria and raised serum creatinine
Why do we screen?
One in three patients with diabetes will be affected by diabetic renal
disease. The presence of microalbuminuria or proteinuria (nephropathy) increases
the risk of large blood vessel disease and premature death by at least a factor
of 2.
How and when do we screen?
Every year at annual review urine should be screened for 'protein loss' - see
flow chart for details. In those with renal changes or renal impairment,
U+E's should also be monitored every 6 months
Definitions
- Microalbuminuria
Albumin - creatinine ratio > 3.0 on 2 occasions
- Proteinuria
Dip positive proteinuria (infection excluded) - confirmed by 24-hour protein
collection
Interventions for people with renal changes
- Optimum glycaemic control - HbAlc < 7%
- ACE inhibitors - to maximum tolerated dose (monitor Serum Creatinine and
Potassium - avoid use in pregnancy)
- Blood pressure control - See chart below
- Other cardiovascular risk factors should be addressed (especially serum
lipids)
Blood pressure targets
| Everyone with diabetes |
140/80 |
| Diabetes, aged > 40 with renal changes |
130/75 |
| Diabetes, aged <40 with renal changes |
120 / 70 |
Benefits of interventions
- Early intervention can preserve renal function, preventing progression to
end stage renal disease
- Late intervention may slow the rate of renal decline to dialysis
- Interventions can reduce other vascular morbidity and mortality
Cautions
- Non-diabetic renal disease is suggested by acute renal decline, haematuria
and short duration of diabetes. Consider further investigations in people
with atypical presentation
- ACE inhibitors can precipitate acute renal failure in people with renal
artery stenosis. This is more likely in the elderly, those with vascular
disease and in people with pre-existing renal impairment. Renal function
should b monitored within a few weeks of starting an ACE inhibitor, within a
few weeks of any significant dose increase, and then every 4 - 6 months
- ACE inhibitors are contraindicated in pregnancy (or women of child bearing
age at risk of pregnancy not using reliable contraception)
- Risks to mother and foetus can be considerable in women with established
renal changes. Seek urgent expert opinion - ideally prior to conception
Diabetes renal screening (EMU available)
The following protocol should only be used if an 'early morning urine' sample
is available
Every patient will be provided with a universal specimen pot and asked to
bring an early morning urine specimen (mid stream) to their annual review
appointment
Urine should be dipped for albumin
Action
- If there is either no albumin or a trace of albumin on dip testing. the
sample should be sent to biochemistry for an albumin - creatinine ratio to
be performed
- If dip positive proteinuria is identified (one plus or more), the specimen
should be sent to microbiology for culture and sensitivity to exclude
infection. If there is no infection, and this is the first time that
proteinuria has been identified, send a 24 hour urine collection to
biochemistry to assess creatinine clearance and 24 hour protein loss.
Interpretation
| Normal |
Negative or trace of albumin on dip testing and an
albumin - creatinine ratio <3.0 |
| Significant |
Negative or trace of albumin on dip testing and an
albumin - creatinine ratio >3.0 |
| Microalbuminuria |
Should only be diagnosed if there have been 2 positive
results (ACR >3.0) within a 6 month period. If this is the first
result, please repeat screening. |
| Proteinuria |
Dip positive for protein in the absence of a urinary
infection, confirmed by a 24 hour protein loss of >300mg. |
The following protocol should be used for all patients who are found to have
dip positive proteinuria
Source: Northumbria NHS Health Care Trust diabetes protocol