Some of your CKD patients will already be managed appropriately because of their current co-morbid conditions, comments Dr Steve Kane-ToddHall

Chronic kidney disease (CKD) is a new term based upon estimated glomerular filtration rate (eGFR) and replaces 'chronic renal impairment' and 'chronic renal failure'. The DH's Renal Services NSF Part 2 deals with the use of eGFRs and the new CKD classification system.1

There are 27 points allocated to CKD in QOF2 (Table 1). Practices must demonstrate that they have established and maintained a disease register of reasonable accuracy. Prevalence rates in an average population should be 5% CKD Stages 3–5 (the vast majority being CKD Stage 3).2–5 Chronic kidney disease is common in atherosclerotic disease, hypertension and diabetes.6–9

One proposal for a new CKD indicator that was not taken up was the regular recording of urinalysis results. GPs should remember to request a urine dip when the eGFR and blood pressure (BP) are checked, as persistent abnormalities on dipstick can independently suggest a diagnosis of CKD and can detect glomerulonephritis.

Table 1: Clinical indicators for chronic kidney disease (CKD)
Disease indicator
Clinical indicator
Points Payment stages
      Min (%) Max (%)
CKD 1
The practice can produce a register of patients aged 18 years and over with CKD (US National Kidney Foundation: Stage 3–5 CKD)
6    
CKD 2
% patients on the CKD register whose notes have a record of blood pressure in the previous 15 months
6 40 90
CKD 3
% patients on the CKD register in whom the last blood pressure reading, measured in the previous 15 months, is 140/85 mmHg or less
11 40 70
CKD 4
% patients on the CKD register with hypertension who are treated with an ACE inhibitor or angiotensin II receptor blocker (unless a contraindication or side-effects are recorded)
4 40 80

Setting up a register (CKD 1)

The register is for those aged over 18 years of age with CKD Stages 3–5. The relevant Read codes are listed in Box 1. There is ample evidence that CKD is both common (up to 10% total prevalence, 5% for CKD Stages 3–5)2–5 and often either undiagnosed (early) or not treated to consistent optimal standards.

This is no surprise. Until recently GPs have had to rely on insensitive creatinine measurements – CKD is generally asymptomatic and uncomplicated until advanced. To date, there has been a lack of quality, evidence-based guidance.

This has changed thanks to the new eGFR-based classification system and CKD Stage-dependent management guidance (Box 2).6–9 It is now possible for:

  • CKD to be diagnosed early, monitored appropriately, and managed in an evidence-based fashion
  • CKD progression to be retarded and complications prevented, hopefully reducing the (currently increasing) demand for renal replacement therapy
  • cardiovascular risk to be reduced
  • end-stage/established renal failure (CKD Stage 5) to be prepared for in a timely fashion (consideration of and preparation for renal replacement therapy by CKD Stage 4)
  • referrals to be managed effectively (vital in the current culture of practice-based commissioning).6,9

A systematic approach to establishing and maintaining the CKD register is vital. Practice computer systems can search and find patients who already meet the criteria for CKD Stages 3–5 by eGFR calculation based on past creatinine measurements – even where they are not currently Read-coded as having renal problems. This is more effective than simply searching existing Read codes as many cases of CKD are currently undiagnosed.

This process should result in only a small number of people with CKD Stages 4–5 with most patients having CKD Stage 3.

Practically, new cases may be identified opportunistically via laboratory reporting of eGFRs or manually using an online calculator based on age, sex, creatinine level and race.9

Screening/case-finding should occur in those particularly at risk of CKD, e.g. patients with diabetes, hypertension, atherosclerotic disease, nephrological/ urological problems, such as chronic pyelonephritis, adult polycystic kidney disease, multisystem disease (e.g. systemic lupus erythematosus, rheumatoid arthritis), and those requiring nephrotoxic medications.6–9

Urinalysis and eGFR are used in screening and all new hospital diagnoses need coding. It has been claimed that >90% of CKD sufferers will already be on a cardiovascular disease register.10

Current guidance requires two eGFR values to be taken (or estimated from past creatinines) at least 3 months apart, with eGFRs <60 confirming CKD Stages 3–5 (Box 2).6,9

Box 1: Chronic kidney disease Read codes
Chronic kidney disease Stage 1
1Z10
Chronic kidney disease Stage 2
1Z11
Chronic kidney disease Stage 3
1Z12
Chronic kidney disease Stage 4
1Z13
Chronic kidney disease Stage 5
1Z14
Angiotensin converting enzyme inhibitor prophylaxis
8B6B
Prophylactic angiotensin II antagonist therapy
EMISQPR5
Renal function monitoring
8A6
Box 2: The classification system for chronic kidney disease6–9
Stage
eGFR* (ml/min/1.73m2)
Other markers of renal damage** required to diagnose
Emphases in management
1
90+
Yes
Consider aetiology and cardiovascular risk; watch CKD Stage 1 and 2 patients for eGFR deterioration
2
60–89
Yes
3
30–59
No
Optimise management of CKD and cardiovascular risk factors; watch for complications
4
15–29
No
Nephrological referral to consider preparation for renal replacement therapy; watch for symptoms
5
<15
No
Consider renal replacement therapy; urgent nephrology consideration

*Beware eGFRs where patient is <18 years of age, pregnant, malnourished, cachetic, oedematous, an amputee, has chronic liver disease or suspected acute renal failure (rapidly rising creatinine level)
**Markers include persistent proteinuria/microalbuminuria/haematuria on urinalysis, abnormalities on ultrasound or other radiological investigations8

Measuring blood pressure (CKD 2)

People on the CKD register should have their BP measured every 15 months. This is an audit standard, with the optimal frequency of monitoring being determined by CKD Stage. This measurement is important because:

  • CKD is an independent cardiovascular risk factor,11 and most CKD patients die from cardiovascular disease9
  • CKD can be caused and progressed by uncontrolled BP.7,12

Many patients with CKD have co-morbidities that require regular BP measurements: atherosclerotic disease, hypertension and diabetes, especially. Practically, frequent BP measurements can be carried out alongside other CKD monitoring investigations (bloods and urinalysis). 6–9

Controlling blood pressure (CKD 3)

The audit standard for BP control in CKD register patients is <140/85 mmHg, measured within the past 15 months. The JBS2 guidelines suggest treating CKD patients with a BP >140/90 mmHg to an optimal BP of <130/80 mmHg (or treating >130/80 mmHg to an optimal BP of <125/75 mmHg where the protein:creatinine ratio is >100 mg/mmol).13–15

Practical tips:

  • consider recording and checking standing BP in the frail elderly, those already on multiple anti-hypertensives, and those with Parkinson's disease, diabetes or falls
  • consider home monitoring or 24-hour BP monitoring where BP seems volatile
  • consider a renal ultrasound and thyroid function tests where BP remains refractory in CKD, i.e. >150/90 mmHg despite three or more anti-hypertensives agents; consider routine referral6,7,9
  • bendroflumethiazide 2.5 mg may be changed for a loop diuretic as thiazides lose some efficacy in CKD Stage 3–4, especially if oedematous.

Medication for CKD patients with hypertension (CKD 4)

Four points are allocated for the prescription of an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin II receptor antagonist (A2RA) in CKD patients who have hypertension. CKD is regarded as target organ damage in the JBS2 guidelines.13 As well as their BP-lowering effect, these drugs are potentially better at retarding the progression of CKD than other anti-hypertensives, possibly even without proteinuria.12,16

Current chronic kidney disease guidelines strictly require an ACE inhibitor/A2RA in patients with diabetes who have higher-risk microalbuminuria or proteinuria, and in those without diabetes but with a urinary protein:creatinine ratio >100 mg/mmol.6,9

An ACE inhibitor remains the firstline choice for patients, with an A2RA being prescribed if ACE inhibitors are contraindicated or not tolerated. My PCT suggests lisinopril as a cost-effective firstline ACE inhibitor, and candesartan as a cost-effective firstline A2RA (irbesartan should be reserved for patients with persistent microalbuminuria or proteinuria).

Practical advice is based on safe prescribing and the detection of acute iatrogenic renal failure and hyperkalaemia:

  • check the eGFR and potassium level by 7–14 days after initiation or dosage change, and then again 28 days after steady dosage is achieved6,7
  • in those at higher risk of deterioration or with renal artery disease (e.g. those on diuretics or with atherosclerotic disease or diabetes) have a low threshold for checking the eGFR, creatine and potassium level at 4 and 10 days and then again at 28 days
  • in those with CKD Stages 4–5, gain the advice of the supervising consultant or a nephrologist before initiating an ACE inhibitor/A2RA (referral or advice is indicated anyway) 6,9
  • where BP is already <130/80 mmHg without an ACE inhibitor/A2RA, consider adding in this medication alongside postural BP monitoring, or possibly swap an existing antihypertensive; where BP is higher than this but is <140/85 mmHg, consider adding in the ACE inhibitor/A2RA, as optimal control is <130/80 mmHg13
  • normally eGFR will fall by less than 15% when introducing an ACE inhibitor/A2RA; if the fall is >15%, consider advice, referral or stopping the drug as this may indicate renal artery stenosis6,9
  • potassium levels may rise – admit if >7.0 mM; where 6.0–6.9 mM, instigate a low potassium diet (avoid LoSalt), avoid oral NSAIDs and potassium-sparing diuretics, re-check the potassium in 7 days and stop the ACE inhibitor/A2RA if hyperkalaemia persists.6,9

Exception reporting

Exception reporting may be necessary if:

  • patient is frail
  • significant co-morbidity (especially terminal illness) exists
  • patient is excluded by secondary care decision
  • there are valid reasons to avoid specific medications (contra-indications, side-effects, falls risk)
  • patient is already on maximal treatment
  • there is informed dissent
  • patient repeatedly refuses to attend.

Exceptions other than those for drug allergies, drug not tolerated or drug contraindicated (Box 3) need to be re-recorded annually. Currently, age alone is not a sufficient reason for excluding a patient, although this has sparked controversy in the medical press.17

Box 3: Chronic kidney disease exception Read codes
Chronic kidney disease quality indicators
9hE..
Patient unsuitable
9hE0.
Informed dissent
9hE1.
Maximum tolerated blood pressure medications
8BL0
Angiotensin converting enzme inhibitors contraindicated
8I28
Angiotensin converting enzme inhibitor not tolerated
8I74
Angiotensin converting enzme inhibitor not indicated
8I64
Angiotensin converting enzme inhibitor declined
8I3D

Conclusion

The addition of CKD in QOF2 will encourage best practice and benefit patients who previously were not diagnosed or not optimally managed. This will cause some increased workload, and will also necessitate tight referrals management and coordinated care between GPs and nephrologists.

The good news for GPs is that many newly diagnosed CKD Stage 3–5 sufferers will already be having regular BP checks and ACE inhibitor/A2RA therapy by virtue of their co-morbidity and the original QOF1 indicators. Practices must have systems in place to ensure regular, structured CKD reviews, reliable call–recall and training for all staff members.

Guidelines in Practice, August 2006, Volume 9(8)
© 2006 MGP Ltd
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