Diabetes Renal Disease
The Joint Diabetes Renal Service at York Hospital: comprises of: Consultant Nephrologist, Diabetologist and Diabetes Nurse Specialist. In addition Multi-Disciplinary Team input from Dietetics, Dialysis Nurses, Podiatrist arranged as required.
Who to refer:
- Patients with eGFR <30 or < 60 & progressively worsening renal function
- With persistent microalbuminuria, nephrotic syndrome, hemoproteinuria
- Those with falling eGFR despite control of proteinuria
- Those with anaemia or Ca < 2.3 (and PTH >10) or Phosphate >1.6
- Raised potassium, metabolic acidosis
- Uncontrolled hypertension/ fluid status
- Anaemia (with normal MCV) and Ferritin
Diabetic nephropathy or diabetic kidney disease affects nearly 20-30% individuals with Type 2 diabetes. The earliest sign of kidney involvement in Type 2 diabetes is abnormal amounts of albumin excretion in the urine which is assessed by laboratory measurement of the albumin creatinine ratio (ACR).
Primary prevention of kidney damage from diabetes centres around the prevention of microvascular (classical diabetic nephropathy) and arterial (and thus renovascular) damage. Early detection and treatment with ACE-I or ARB agents are proven to slow the progression of renal diseasecaused by diabetes. In addition tight BP control and optimised diabetes control provide added protection.
We discuss here include how often and by what means to detect and confirm the possibility of diabetic renal disease, and the means of monitoring its progression. In those with detected renal disease, issues arise as to the means to reduce or stop such progression, and the point at which to engage specialist renal management.
Urine dipstick tests are subject to false positives because of patient dehydration, hematuria, exercise, infection etc. Conversely, dipstick tests also are subject to false negatives as a result of excessive hydration and urine proteins other that albumin. Dipstick tests are therefore a poor screening test to detect early diabetic nephropathy.
- Ask all people with or without detected nephropathy to bring in a first-pass morning urine specimen once a year. In the absence of proteinuria/urinary tract infection (UTI), send this for laboratory estimation of albumin:creatinine ratio (ACR). Request a specimen on a subsequent visit if UTI prevents analysis
- Make the measurement on a spot sample if a first-pass sample is not provided(and repeat on a first-pass specimen if abnormal) or make a formal arrangement for a first-pass specimen to be provided
- Repeat the test if an abnormal ACR is obtained (in the absence of proteinuria/UTI)at each of the next two clinic visits but within a maximum of 3-4 months. Take the result to be confirming microalbuminuria if a further specimen (out of two more) is also abnormal(>2.5 mg/mmol for men, >3.5 mg/mmol for women)
- Measure serum creatinine and estimate the glomerular filtration rate (eGFR) annually at the time of albumin:creatinine ratio estimation.
Suspect renal disease, other than diabetic nephropathy and consider further investigation or referral when the albumin:creatinine ratio (ACR) is raised and any of the following apply:
- There is no significant or progressive retinopathy
- Blood pressure is particularly high or resistant to treatment
- Had a documented normal ACR and develops heavy proteinuria (ACR >100 mg/mmol)
- Significant haematuria is present
- The glomerular filtration rate has worsened rapidly
- The person is systemically ill
Targets for a person with an abnormal albumin:creatinine ratio:
- Tight Blood Glucose control - Target HbA1c 48 - 53 mmol/mol (individualisation of targets is recommended in partnership with the patient)
- Maintain blood pressure below 130/80 mm Hg (consider falls risk and adjust target)
- ACE inhibitors or Angiotensin II receptor blockers (ARB's) are recommended first line drugs (unless contraindicated)
- Calcium channel blocker (non-dihydropyridine class) drugs and low dose thiazide diuretics are useful second line agents
- Loop diuretics are useful in the presence of volume overload (e.g.leg edema)
- Additional antihypertensive therapy may be required.
- Combination therapy with ACEinhibitor and ARB has superior anti-proteinuric effect, however watch out for hyperkalemia
- Treat dyslipidemia (serum cholesterol, LDL cholesterol and triglycerides treated to targets)
- Aspirin therapy if indicated
- Lifestyle changes, weight loss and smoking cessation should be advised
- Dietary protein restriction is not routinely advised
- Patient education is an integral part of overall management
Treatment with ACE-I or ARB: For those with confirmed raised albumin excretion rate (>2.5 mg/mmol for men, >3.5 mg/mmol for women).
- Start ACE inhibitors or ARB (if ACE-I intolerant) and titrate to full dose in all individual.
When starting ACE-I or ARB:
- Caution in individuals with impaired kidney function
- Assess kidney function and electrolytes 1-2 weeks after initiating therapy, watch out for hyperkalemia
- Assess kidney function after any subsequent increase in dose
- Small rise in creatinine or a mild fall in eGFR values is expected with therapy
- STOP therapy - If serum creatinine rises by >30% or >25% fall in estimated GFR and seek specialist advice (to exclude possible renovascular disease)
Have an informed discussion before starting an ACE inhibitor in a woman for whom there is a possibility of pregnancy, assessing the relative risks and benefits of the use of the ACE inhibitor